1
City UniversityDhakaBangladesh
Assignment OnTypes of Diodehelliphellip
Cource titleElectronic Circuit I
Cource Code EEE301 Submitted by Robioul AwalID153103022
Batch10th
FacebookbcomRobioul999
2
Submission date7-02-2017
What is a Diodehelliphelliphellip
A Diode is the simplest two-terminal unilateral semiconductor device It allows current to flow only in one direction and blocks the current that flows in the opposite direction The two terminals of the diode are called as anode and cathode The symbol of diode is as shown in the figure below
characteristics of a diode
How Diodes workhellipThe diode operates when a voltage signal is applied across its terminals The application of a DC voltage to make the diode operate in a circuit is called as lsquoBiasingrsquo As already mentioned above the diode resembles to that of a one way switch so it can either be in a state of conduction or in a state of non conduction The lsquoONrsquo state of a diode is achieved by lsquoForward biasingrsquo which means that positive or higher potential is applied to the anode and negative or lower potential is applied at the cathode of the diode In other words the lsquoONrsquo state of diode has the applied current in the same direction of the arrow head The lsquoOFFrsquo state of a diode is achieved by lsquoReverse biasingrsquo which means that positive or higher potential is applied to the cathode and negative or lower potential is applied at the anode of the diode In other words the lsquoOFFrsquo state of diode has the applied current in the opposite direction of the arrow head
During lsquoONrsquo state the practical diode offers a resistance called as the lsquoForward resistancersquo The diode requires a forward bias voltage to switch to the lsquoONrsquo condition which is called Cut-in-voltage The diode starts conducting in reverse biased mode when the reverse bias voltage exceeds its limit which is called as the Breakdown voltage The diode remains in lsquoOFFrsquo state when no voltage is applied across it
3
A simple p-n juction diode is fabricated by doping p and n type layers on a silicon or germanium wafer The germanium and silicon materials are prefered for diode fabrication becausemiddot They are available in high purity Slight doping like one atom per ten million atoms of a desired impurity can change the conductivity to a considerable level The properties of these materials change on applying heat and light and hence it is important in the devlopment of heat and light sensetive devices
Types of Diode The types of diode are as follow-
1 Zener diode2 P-N junction diode3 Tunnel diode4 Varactor diode5 Schottky diode6 Photo diode7 PIN diode8 Laser diode9 Avalanche diode10Light emitting diode
1Zener diodes Zener diodes are semiconductor diodes which have been manufactured to have their reverse breakdown occur at a specific well-defined voltage (its ldquoZener voltagerdquo) and that are designed such that they can be operated continuously in that breakdown mode Commonly available Zener diodes are available with breakdown voltages (ldquoZener voltagesrdquo) anywhere from 18 to 200 V
4
The schematic symbol for a Zener diode is shown abovendash it is very similar to that of a regular diode but with bent edges on the bar The Zener still conducts electricity in the forward direction like any other diode but also conducts in the reverse direction if the voltage applied is reversed and larger than the Zener breakdown voltage
V-I characteristicsThe V-I Characteristics of a Zener Diode can be divided into two parts
Forward Characteristics
Reverse Characteristics
5
Advantages amp DisadvantagesAdvantages
Control of flowing current
Size and Expense
Performance
Compatibility and Obtainability
DisadvantagesZener diodes cancel out voltages by applying even larger voltages in the reverse
6
direction wasting electricity in the process Additionally Zener diodes have a relatively poor regulation ratio and are generally not as good as transistors
2Tunnel Diode
IV CharacteristicsAs forward bias is applied significant I is produced
After continuous increase of V the current achieves its minimum value called as Valley Current After further increase in V current start increasing as ordinary diode
7
Advantage
1 environmental immunity2 Low cost3 Simplicity4 Low noise5 High speed6 Low power consumption
Disadvantage
Only disadvantage of tunnel diode are its low output voltage swing and it is a two terminal device hence there is no isolation between input and output hence transistor is used along with a tunnel diode for frequencies below 1 GHz
3Varactor diode
Varactor Diode is a reverse biased p-n junction diode whose capacitance can be varied electrically As a result these diodes are also referred to as varicaps tuning diodes voltage variable
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
2
Submission date7-02-2017
What is a Diodehelliphelliphellip
A Diode is the simplest two-terminal unilateral semiconductor device It allows current to flow only in one direction and blocks the current that flows in the opposite direction The two terminals of the diode are called as anode and cathode The symbol of diode is as shown in the figure below
characteristics of a diode
How Diodes workhellipThe diode operates when a voltage signal is applied across its terminals The application of a DC voltage to make the diode operate in a circuit is called as lsquoBiasingrsquo As already mentioned above the diode resembles to that of a one way switch so it can either be in a state of conduction or in a state of non conduction The lsquoONrsquo state of a diode is achieved by lsquoForward biasingrsquo which means that positive or higher potential is applied to the anode and negative or lower potential is applied at the cathode of the diode In other words the lsquoONrsquo state of diode has the applied current in the same direction of the arrow head The lsquoOFFrsquo state of a diode is achieved by lsquoReverse biasingrsquo which means that positive or higher potential is applied to the cathode and negative or lower potential is applied at the anode of the diode In other words the lsquoOFFrsquo state of diode has the applied current in the opposite direction of the arrow head
During lsquoONrsquo state the practical diode offers a resistance called as the lsquoForward resistancersquo The diode requires a forward bias voltage to switch to the lsquoONrsquo condition which is called Cut-in-voltage The diode starts conducting in reverse biased mode when the reverse bias voltage exceeds its limit which is called as the Breakdown voltage The diode remains in lsquoOFFrsquo state when no voltage is applied across it
3
A simple p-n juction diode is fabricated by doping p and n type layers on a silicon or germanium wafer The germanium and silicon materials are prefered for diode fabrication becausemiddot They are available in high purity Slight doping like one atom per ten million atoms of a desired impurity can change the conductivity to a considerable level The properties of these materials change on applying heat and light and hence it is important in the devlopment of heat and light sensetive devices
Types of Diode The types of diode are as follow-
1 Zener diode2 P-N junction diode3 Tunnel diode4 Varactor diode5 Schottky diode6 Photo diode7 PIN diode8 Laser diode9 Avalanche diode10Light emitting diode
1Zener diodes Zener diodes are semiconductor diodes which have been manufactured to have their reverse breakdown occur at a specific well-defined voltage (its ldquoZener voltagerdquo) and that are designed such that they can be operated continuously in that breakdown mode Commonly available Zener diodes are available with breakdown voltages (ldquoZener voltagesrdquo) anywhere from 18 to 200 V
4
The schematic symbol for a Zener diode is shown abovendash it is very similar to that of a regular diode but with bent edges on the bar The Zener still conducts electricity in the forward direction like any other diode but also conducts in the reverse direction if the voltage applied is reversed and larger than the Zener breakdown voltage
V-I characteristicsThe V-I Characteristics of a Zener Diode can be divided into two parts
Forward Characteristics
Reverse Characteristics
5
Advantages amp DisadvantagesAdvantages
Control of flowing current
Size and Expense
Performance
Compatibility and Obtainability
DisadvantagesZener diodes cancel out voltages by applying even larger voltages in the reverse
6
direction wasting electricity in the process Additionally Zener diodes have a relatively poor regulation ratio and are generally not as good as transistors
2Tunnel Diode
IV CharacteristicsAs forward bias is applied significant I is produced
After continuous increase of V the current achieves its minimum value called as Valley Current After further increase in V current start increasing as ordinary diode
7
Advantage
1 environmental immunity2 Low cost3 Simplicity4 Low noise5 High speed6 Low power consumption
Disadvantage
Only disadvantage of tunnel diode are its low output voltage swing and it is a two terminal device hence there is no isolation between input and output hence transistor is used along with a tunnel diode for frequencies below 1 GHz
3Varactor diode
Varactor Diode is a reverse biased p-n junction diode whose capacitance can be varied electrically As a result these diodes are also referred to as varicaps tuning diodes voltage variable
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
3
A simple p-n juction diode is fabricated by doping p and n type layers on a silicon or germanium wafer The germanium and silicon materials are prefered for diode fabrication becausemiddot They are available in high purity Slight doping like one atom per ten million atoms of a desired impurity can change the conductivity to a considerable level The properties of these materials change on applying heat and light and hence it is important in the devlopment of heat and light sensetive devices
Types of Diode The types of diode are as follow-
1 Zener diode2 P-N junction diode3 Tunnel diode4 Varactor diode5 Schottky diode6 Photo diode7 PIN diode8 Laser diode9 Avalanche diode10Light emitting diode
1Zener diodes Zener diodes are semiconductor diodes which have been manufactured to have their reverse breakdown occur at a specific well-defined voltage (its ldquoZener voltagerdquo) and that are designed such that they can be operated continuously in that breakdown mode Commonly available Zener diodes are available with breakdown voltages (ldquoZener voltagesrdquo) anywhere from 18 to 200 V
4
The schematic symbol for a Zener diode is shown abovendash it is very similar to that of a regular diode but with bent edges on the bar The Zener still conducts electricity in the forward direction like any other diode but also conducts in the reverse direction if the voltage applied is reversed and larger than the Zener breakdown voltage
V-I characteristicsThe V-I Characteristics of a Zener Diode can be divided into two parts
Forward Characteristics
Reverse Characteristics
5
Advantages amp DisadvantagesAdvantages
Control of flowing current
Size and Expense
Performance
Compatibility and Obtainability
DisadvantagesZener diodes cancel out voltages by applying even larger voltages in the reverse
6
direction wasting electricity in the process Additionally Zener diodes have a relatively poor regulation ratio and are generally not as good as transistors
2Tunnel Diode
IV CharacteristicsAs forward bias is applied significant I is produced
After continuous increase of V the current achieves its minimum value called as Valley Current After further increase in V current start increasing as ordinary diode
7
Advantage
1 environmental immunity2 Low cost3 Simplicity4 Low noise5 High speed6 Low power consumption
Disadvantage
Only disadvantage of tunnel diode are its low output voltage swing and it is a two terminal device hence there is no isolation between input and output hence transistor is used along with a tunnel diode for frequencies below 1 GHz
3Varactor diode
Varactor Diode is a reverse biased p-n junction diode whose capacitance can be varied electrically As a result these diodes are also referred to as varicaps tuning diodes voltage variable
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
4
The schematic symbol for a Zener diode is shown abovendash it is very similar to that of a regular diode but with bent edges on the bar The Zener still conducts electricity in the forward direction like any other diode but also conducts in the reverse direction if the voltage applied is reversed and larger than the Zener breakdown voltage
V-I characteristicsThe V-I Characteristics of a Zener Diode can be divided into two parts
Forward Characteristics
Reverse Characteristics
5
Advantages amp DisadvantagesAdvantages
Control of flowing current
Size and Expense
Performance
Compatibility and Obtainability
DisadvantagesZener diodes cancel out voltages by applying even larger voltages in the reverse
6
direction wasting electricity in the process Additionally Zener diodes have a relatively poor regulation ratio and are generally not as good as transistors
2Tunnel Diode
IV CharacteristicsAs forward bias is applied significant I is produced
After continuous increase of V the current achieves its minimum value called as Valley Current After further increase in V current start increasing as ordinary diode
7
Advantage
1 environmental immunity2 Low cost3 Simplicity4 Low noise5 High speed6 Low power consumption
Disadvantage
Only disadvantage of tunnel diode are its low output voltage swing and it is a two terminal device hence there is no isolation between input and output hence transistor is used along with a tunnel diode for frequencies below 1 GHz
3Varactor diode
Varactor Diode is a reverse biased p-n junction diode whose capacitance can be varied electrically As a result these diodes are also referred to as varicaps tuning diodes voltage variable
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
5
Advantages amp DisadvantagesAdvantages
Control of flowing current
Size and Expense
Performance
Compatibility and Obtainability
DisadvantagesZener diodes cancel out voltages by applying even larger voltages in the reverse
6
direction wasting electricity in the process Additionally Zener diodes have a relatively poor regulation ratio and are generally not as good as transistors
2Tunnel Diode
IV CharacteristicsAs forward bias is applied significant I is produced
After continuous increase of V the current achieves its minimum value called as Valley Current After further increase in V current start increasing as ordinary diode
7
Advantage
1 environmental immunity2 Low cost3 Simplicity4 Low noise5 High speed6 Low power consumption
Disadvantage
Only disadvantage of tunnel diode are its low output voltage swing and it is a two terminal device hence there is no isolation between input and output hence transistor is used along with a tunnel diode for frequencies below 1 GHz
3Varactor diode
Varactor Diode is a reverse biased p-n junction diode whose capacitance can be varied electrically As a result these diodes are also referred to as varicaps tuning diodes voltage variable
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
6
direction wasting electricity in the process Additionally Zener diodes have a relatively poor regulation ratio and are generally not as good as transistors
2Tunnel Diode
IV CharacteristicsAs forward bias is applied significant I is produced
After continuous increase of V the current achieves its minimum value called as Valley Current After further increase in V current start increasing as ordinary diode
7
Advantage
1 environmental immunity2 Low cost3 Simplicity4 Low noise5 High speed6 Low power consumption
Disadvantage
Only disadvantage of tunnel diode are its low output voltage swing and it is a two terminal device hence there is no isolation between input and output hence transistor is used along with a tunnel diode for frequencies below 1 GHz
3Varactor diode
Varactor Diode is a reverse biased p-n junction diode whose capacitance can be varied electrically As a result these diodes are also referred to as varicaps tuning diodes voltage variable
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
7
Advantage
1 environmental immunity2 Low cost3 Simplicity4 Low noise5 High speed6 Low power consumption
Disadvantage
Only disadvantage of tunnel diode are its low output voltage swing and it is a two terminal device hence there is no isolation between input and output hence transistor is used along with a tunnel diode for frequencies below 1 GHz
3Varactor diode
Varactor Diode is a reverse biased p-n junction diode whose capacitance can be varied electrically As a result these diodes are also referred to as varicaps tuning diodes voltage variable
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
8
capacitor diodes parametric diodes and variable capacitor diodes
Characteristics1Low-noise characteristic produce much less noise than most conventional amplifiers2Low Cost3High Realibity4Light Weath
5Small Size
Advantage It is basically an electrically controlled variable capacitor no moving parts needa monitored voltage source to hold the value temperature sensitive Si based
Disadvantagedont work over 100C variable capacitors in the mechanical adjusted variety work with higher voltages arent voltage spike sensitive and are far more rugged are in picofarad to micro farad range can handle many kilowatts set and forget dont need controls to maintain capacitance arent temperature sensitive can be motor driven for electric control
4 Schottky diode
Schottky diode it is also referred to as Schottky barrier diode or as hot carrier diode This is a diode with semiconductor-metal junction This device can simply rectify frequencies greater than 300 MHz Its forward
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
9
voltage drop is also very low (015 to 045 V) This results in higher switching speed and improved system efficiency The junction in the diode is formed by the metal (such as gold tungsten chromium platinum molybdenum or certain silicides) and N-type doped silicon semiconductor
V-I characteristics of Schottky Diode
Schottky diode I-V characteristicsSchottky diode is a metal-semiconductor (MS) diodeHistorically Schottky diodes are the oldest diodesMS diode electrostatics and the general shape of the MS diode I-V characteristics are similar to p+n diodes but the details of current flow are different Dominant currents in a p+n diodearise from recombination in the depletion layer under small forward biasarise from hole injection from p+ side under larger forward biasDominant currents in a MS Schottky diodesElectron injection from the semiconductor to the metal
Advantages
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
10
DisadvantageshellipLimitations The most evident limitations of Schottky diodes are the relatively low reverse voltage ratings for silicon-metal Schottky diodes typically 50 V and below and a relatively high reverse leakage current Some higher-voltage designs are available 200V is considered a high reverse voltageReverse leakage current because it increases with temperature leads to a thermal instability issue This often limits the useful reverse voltage to well below the actual ratingWhile higher reverse voltages are achievable they would be accompanied by higher forward voltage drops comparable to other types such a Schottky diode would have no advantage
5Photodiode
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
11
A photodiode is one type of light detector used to convert the light into current or voltage based on the mode of operation of the device
It comprises of optical filters built-in lenses and also surface areas These diodes have a slow response time when the surface area of
the photodiode increases Photodiodes are alike to regular semiconductor diodes
V-I Characteristics of Photodiode
V-I characteristics The voltage-current equation for photodiode is given by following equation P I = I (eV ηVT minus1) minus I0 (1)Here I0 reverse saturation current V applied potential to diode VT voltage equivalent to temperature=KTe ηconstant (=1 for Ge and 2 for Si) IP photo current The photocurrent is product of responsivity of photo diode and power of incident light ie IP=RλP The responsivity of a photodiode is a measure of the sensitivity to light and it is defined as the ratio of the photocurrent IP to the incident light power P at a given wavelength In the forward biased condition the current through diode increases exponentially But in thereverse biased diode V is negative hence the exponential term becomes less than 1 therefore hellipthe equation becomes as IR = minusI0 ndash IP
Using of photo Diode
Cameras Medical devices Safety equipment Optical communication devices Position sensors Bar code scanners Automotive devices Surveying instruments
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
12
Advantages of photodiode
1 can be used as variable resistance device2 Highly sensitive to the light3 The speed of the operation is very high the switching of current and hence
the resistance value from high to low or other wise is very fast
Disadvantages of photodiode(i) The dark current is temperature dependent (ii) The overall photo diode characteristics are temperature dependent Hence
have poor temperature stability(iii) The current and change in current is in the range of TA which may not be
sufficient to drive other circuits Hence amplification is necessary
6Pin diode
The PIN diode is a one type of photo detector used to convert optical signal into an electrical signal The PIN diode comprises of three regions namely P-region I-region and N-
region Typically both the P and N regions are heavily doped due to they are utilized for Ohmic contactsThe intrinsic region in the diode is in contrast to a PN junction diode This region makes the PIN diode an lower rectifier but it makes it appropriate for fast switches
attenuators photo detectors and applications of high voltage power electronics
IV-Characteristics of PIN DiodeThe forward series resistance characteristic and the reverse capacitance characteristic are shown graphically in Below Figure for a typical pin diode The pin diode is used as a dc-controlled microwave switch operated by rapid changes in bias or as a modulating device that takes advantage of the variable forward-resistance characteristic Since no recti1048619cation occurs at the pn junction a highfrequency signal can be modulated (varied) by a lower-frequency bias variation A pin diode can also be used in attenuator applications because its resistance can be controlled by the amount of
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
13
current Certain types of pin diodes are used as photodetectors in fiber-optic systems
Advantages of PIN diode
High voltage rectfier The PIN diode can be used as a high voltage recti1048619er The intrinsic region provides a greater separationbetween the PN and N regions allowing higher reverse voltages to be tolerated
RF switchThe PIN diode makes an ideal RF switch The intrinsic layer between the P and N regions increases the distancebetween them This also decreases the capacitance between them thereby increasing he level of isolation when the diode isreverse biased
Photodetector As the conversion of light into current takes place within the depletion region of a photdiode increasing thedepletion region by adding the intrinsic layer improves the performance by increasing he volume in which light conversionoccurs
Disadvantages of PIN diodeHas a reverse recovery time which contributes to power loss
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
14
7Avalanche Diode
An avalanche diode is a special type of semiconductor device designed to operate in reverse breakdown region Avalanche diodes are used as relief valves (a type of valve used to control the pressure in a system) to protect electrical systems from excess voltages
How avalanche diode works
IV-Characteristics of Avalance Diode
In electronics an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage
Current-voltage characteristics of electrical components and circuits can be collected in two ways
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
15
1 When potentiostatic access to connect to the electrode voltage Applied voltage
then gradually increase until it reaches the final voltage 2 In galvanostatic approach set stream which is then gradually increased to a final
current
Avalanche photodiode advantages and disadvantagesThe avalanche photodiode has a number of different characteristics to the normal p-n or p-i-n photodiodes making them more suitable for use in some applications In view of this it is worth summarising their advantages and disadvantages
The main advantages of the avalanche photodiode include
Greater level of sensitivity
The disadvantages of the avalanche photodiode include
Much higher operating voltage may be required
Avalanche photodiode produces a much higher level of noise than a p-n photodiode
Avalanche process means that the output is not linear
8Laser Diode
A laser diode also known as an injection laser or diode laser is a semiconductor device that produces coherent radiation (in which the waves are all at the same frequency and phase) in the visible or infrared (IR) spectrum when current passes through it Laser diodes are
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
16
used in optical fiber systems compact disc (CD) players laser printers remote-control devices and intrusion detection systems
IV-Characteristics of Laser Diode
The laser diode specification for the forward voltage across the diode is required in a number of areas of the design Often laser diode manufacturers prefer to place the voltage on the vertical axis
From the diagram it can be seen that the voltage across the laser diode is typically around 15 volts although it is necessary to check for the particular laser diode in question The forward voltage specification will vary according to the materials used in the diode current etc
Although the forward voltage does vary with temperature this is not normally a major consideration
Advantages of Diode LasersCompared to most laser types diode lasers are less expensive and more compact making them ideal for small electronic devices such as CD and DVD players CD-ROMs DVD-ROMs and other optical data storage devices Laser printers laser fax machines and supermarket bar code readers all use diode lasers Using helium-neon lasers increases the size of these devices by as much as five times Diode lasers use much less power than most types of lasers While gas and solid-state lasers require a power supply in kilo-volts diode lasers typically run on small volt batteries
Disadvantages of Diode LasersDiode laser beams are highly divergent meaning wedge-shaped instead of straight and parallel and have shorter coherent distances which makes for inferior quality in optics performance They are not as well-suited as helium-neon lasers for high-quality holography Moreover semiconductors in electronic devices are prone to static electrical discharges meaning diode lasers in these gadgets can be damaged by unstable and fluctuating power supply Also prone to gradual aging diode lasers over time use increasing amounts of power with diminishing efficiency
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
17
The lens required for beam correction adds to the diode lasers fragility such that damage to the lens renders the laser non-functional
9Light Emitting Diode (LED)
The holes are present in the valance band and the free electrons are in the conduction band When a p-n junction is forward biased the electron from n-type semiconductor material cross the p-n junction and combine with the holes in the p-type semiconductor material Thus with respect to the holes the free electrons are at higher energy level
IV-Characteristics of (LED)
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
18
For a Light Emitting Diode to emit any form of light it needs a current to flow through it as it is a current dependant device As the LED is to be connected in a forward bias condition across a power supply it should be current limited using a series resistor to protect it from excessive current flow From the graph above we can see that each LED has its own forward voltage drop across the PN-junction and this parameter which is determined by the semiconductor material used is the forward voltage drop for a given amount of forward conduction current
Advantage gt LEDs produce more light per watt than do incandescent bulbs this is useful in battery powered or energysaving devices
Disadvantage gt LED performance largely depends on the ambient temperature of the operating environment Driving the LED hard in high ambient temperatures may result in overheating of the LED package eventually leading to device failure
10P-N Junction Diode
A pndashn junction is a boundary or interface between two types of semiconductor material p-type and n-type inside a single crystal of semiconductor The p (positive) side contains an excess of holes while the n (negative) side contains an excess of electrons
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
19
Typically at room temperature the voltage across the depletion layer for silicon is about 06 ndash 07 volts and for germanium is about 03 ndash 035 volts This potential barrier will always exist even if the device is not connected to any external power source as seen in diodes
Advantage The world is going to be easy by using this diode day by day
P-n Junction I-V Characteristics
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
20
In Equilibrium the Total current balances due to the sum of the individual components
Submitted by
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You
21
Robioul Hasan
BSC in EEE
City University of Bangladesh
FacebookcomRobioul999
Thank You