New Sample I-V , PL & PLENew Sample I-V , PL & PLE

Toshiyuki Ihara

’04 07/05

Sample informationSample information• n-type-doped single wire

5_7_04.1(accumulation) 5_7_04.2 (depletion)

#1 Perfect I-V, PL & PLE

#2 Perfect

#3 Perfect – isolated lines practice

#4 Poor – lots of lines

#5 Perfect I-V, PL

#1 Poor – lots of lines

#2 Perfect

#3 Perfect I-V

#4 Perfect – Scattered lines

#5 Bad

#6 Bad practice

I measured I-V of sample 5_7_04.1 #1,#5 and 5_7_04.2 #3

PL & PLE spectra of 5_7_04.1 #1are novel data.

(I have shown the PL data of sample 5_7_04.1 #5)

I-V measurement introductionI-V measurement introduction• I applied 4 electrodes to each sample

– A,B : Gate– C,D : Earth (stem)

• I measured I-V between these 4 electrodes at the temperature of 5K and 300K.

• However, I found that some electrodes don’t work properly because of insulations.

I-V measurementI-V measurement• Sample 5_7_04.1 #5 (accumulation)

gate - earth I- V

- 5.00E- 07

0.00E+00

5.00E- 07

1.00E- 06

1.50E- 06

2.00E- 06

2.50E- 06

- 0.2 0 0.2 0.4 0.6 0.8

voltage [V]

curr

ent

[A]

gate - gate ohmic

- 3.00E- 05

- 2.00E- 05

- 1.00E- 05

0.00E+00

1.00E- 05

2.00E- 05

3.00E- 05

- 0.2 - 0.1 0 0.1 0.2voltage [V]

curr

ent

[A]

earth - earth ohmic

- 3.00E- 05

- 2.00E- 05

- 1.00E- 05

0.00E+00

1.00E- 05

2.00E- 05

3.00E- 05

- 0.15 - 0.1 - 0.05 0 0.05 0.1 0.15

voltage [V]

curr

ent

[A]

300K 5K

300K

300K

A-B (gate–gate)

C-D (earth–earth)

A-C (gate–earth)

gate - earth I- V

- 1.00E- 06

- 5.00E- 07

0.00E+00

5.00E- 07

1.00E- 06

1.50E- 06

2.00E- 06

- 0.2 0 0.2 0.4 0.6 0.8 1

gate voltage (V)

curr

ent

(A)

I-V measurementI-V measurement• Sample 5_7_04.1 #1 (accumulation)

• Small leak current

80nA / 0.8V at 5K

300K 5K

gate - earth I- V

- 1.00E- 05

- 8.00E- 06

- 6.00E- 06

- 4.00E- 06

- 2.00E- 06

0.00E+00

2.00E- 06

4.00E- 06

6.00E- 06

8.00E- 06

- 0.1 - 0.05 0 0.05 0.1

gate voltage (V)

curr

ent

(A) A- C

A- DB- C

B- D

I-V measurementI-V measurement• Sample 5_7_04.2 #3 (depletion)

• Gate-earth I-V : Ohmic current…– Process failure?

– Nature of high-dope

sample(accumulation)??

300K

PL & PLE measurement introductionPL & PLE measurement introduction• I measured PL scan, wire & arm PL and PLE Vg

dependence of sample 5_7_04.1 #1(depletion type)

• It is hard to measure PLE spectra by previous method ( integral all emission aria) because it is very difficult to decrease the scattered laser.

• I changed integral aria

from all emission

to low energy tail.

PL scan PL scan ～ ～ sample qualitysample quality

50

40

30

20

10

x103

1.6001.5901.5801.5701.560

a040629003accumulation n- type doped QWR 5-7-04.1 #1 perfect 50m scan1m step (0 - 50m)t = 5 sT = 3.517 KV = 0.25Vlaser 745nmNDex 1/ 10, 1/ 1000 (...100W ?)

50

40

30

20

10x1

03

1.6001.5901.5801.5701.560

a040629005accumulation n- type doped QWR 5-7-04.1 #1 perfect 50m scan1m step (100 - 150m)t = 5 sT = 3.517 KV = 0.25Vlaser 745nmNDex 1/ 10, 1/ 1000 (...100W ?)

0 - 100μm

(1μm step)

Vg = 0.25V

Laser 10μW

stem excitation

(1.665eV)

Reflection geometry

Still some ML fluctuations…

Wire PL & PLE Vg dependenceWire PL & PLE Vg dependenceWire normalized PL

& PLE spectra

Almost same result as before (for ICPS)

①exciton blue shift

② trion doesn’t shift

③ Ex – Ex- increases

④trion→plasma

(0.3V - 0.5V)

⑤PLE shape at high voltage (0.8V)

※No irregular PLE absorption peak

(arrow)

040705005 - 040705012

1.57 1.575 1.58 1.585

040705013 - 017

1.565 1.57 1.575 1.58 1.585 1.59

X

X-

FES

BOWA※

This is because the PL integral aria is narrow (low energy tail )

Integral aria

Arm PL & PLE Vg dependenceArm PL & PLE Vg dependenceArm well normalized PL & PLE

spectra

Not the same result as before

①cannot resolve X absorption and X- absorption

② PL peak (unknown origin)

040705018 - 023

1.58 1.585 1.59 1.595 1.6 1.605

①

②

X

X-