View
227
Download
0
Category
Preview:
Citation preview
ESCOLA POLITÉCNICA – USP
THEORETICAL MODELINGOF NANOSTRUCTURED
MATERIALS
PROF. JOÃO F. JUSTO
ELECTRONIC SYSTEMS ENGINEERING DEPARTMENT
OUTLINE
Physical properties of materials
Nanoscale investigations at EPUSP
Theoretical modeling of materials
Properties of nanostructured materials
MATERIALS SCIENCE
“Materials science is the subject that brings together most of the engineering areas”.
Applications: alloys, nanoelectronic devices, reinforced metals, polymeric materials.
Understand matter at nanoscopic level.
NANOSCIENCE AT EP-USP
Prof. Jorge Tenório: synthesis of carbon nanomaterials
Prof. Andre Tschiptschin: characterization of thin films
Prof. Fernando Fonseca: nanosensors
Prof. Francisco Valenzuela: clay nanoparticles
Profa. Luciana Kassab: nanoparticles in glasses
Prof. João Justo: modeling of nanosystems for nanoelectronics
dielectricmetallic contact
substrate
insulating layerconducting channel
CHALLENGES IN MICROELECTRONICS
ATOMIC ORGANIZED SYSTEMS
CONDENSEDSYSTEMS
MOLECULARSYSTEMS
ATOMISTIC SIMULATIONS
INTERATOMIC INTERACTIONS
EQUATIONS OF MOTION
PHYSICAL PROPERTIES
INTERATOMIC INTERACTIONS
CLASSICAL APPROACH
QUANTUM APPROACH
),......,,( 21 Ni rrrVF
)()()()(2
22
iIiii rErrVrm
EQUATIONS OF MOTION
MOLECULAR DYNAMICS
MONTE CARLO (Metropolis)
MINIMIZATION METHODS(Stepest Descent ou Conjugate Gradient)
),........,( 12
2
Ni
ii rrVdt
rdmF
PHYSICAL PROPERTIES OF MATERIALS
STRUCTURAL PROPERETIES◊ lattice parameters ◊ elasticity◊ vibrational modes◊ thermodinamical properties
ELECTRONIC AND MAGNETIC PROPERTIES◊ electronic band structure◊ magnetism◊ electronic mobility◊ dielectric properties
DEFECTS IN SEMICODUTORS
DOPANTS
DEFECT ENGINEERING
IONIC IMPLANTATIONBENEFICIAL
DETRIMENTAL
HYDROGENATION
PASSIVATION
TERMALIZATION
IONIC IMPLANTATION
IMPURITIES IN SEMICONDUTORS
IMPURITIES IN DIAMOND, GaAs, BNGaN, SiC
ENERGETICS OF IMPURITIES
ELETRONIC AND OPTICAL PROPERTIES
MAGNETISM
(Justo et al., Phys. Rev. B, 2009)(Justo et al., Appl. Phys. Lett., 2006)(Justo et al., Phys. Rev. B, 2011)
migration trajectory
electronic structure
conduction band
valence band
aaaaaaaaaa
aa
NANOELECTRONIC DEVICES
NEW GENERATION OF NANODEVICES
Nanotubes Nanowires Molecules Graphene
SEMICONDUCTING NANOWIRES
STRUCTURAL PROPERTIES OFSILICON NANOWIRES
STABILITY AND PLASTICITY
SCALING LAWS
ELETRONIC PROPERTIES
TIN OXIDE NANOWIRES
σσ
(Justo et al., Phys. Rev. B 2007)(Justo et al., J. Phys. Chem. C, 2012)(Justo , in Trends in Computational Nanomechanics, 2010)
DIAMONDOIDS
1610HCfundamental building blocks(Merkle, Nanotechnology 2000)
electron emission devices(Yang, Science 2007)
HYDROCARBON
SUCESS IN SIZE SEPARATION(Dahl et al., Science 2003)
MOLECULAR CRYSTALS
ADAMANTANE
FUNDAMENTAL BUILDING BLOCKS
MOLECULAR CRYSTALS
(Justo et al., Phys. Rev. B, 2009)(Justo et al., J. Phys. Condens. Mat., 2010)
• large cohesive energy
• large bulk modulus
1610HC
A
NHC 1710
NHC 2112
amantadine
rimantadine
NANODIAMOND:MEDICAL APPLICATIONS
USED IN TREATING INFLUENZA, PARKINSON AND DEPRESSION
“DRUG DELIVERY”
(Justo et al., J. Phys. Chem. A, 2010)
M2 channel
GROUP IV GRAPHENE
GROUP-IV GRAPHENE (C, Si, Ge, Sn)
HYDROGRNATION AND FLUORINATION
ELECTRONIC BAND STRUCTURE
graphene graphane
(Justo et al, J. Phys. Chem. C, 2011)
SUMMARY
NANOSCIENCE VS. NANOTECHNOLOGY
(understand properties to build nanosystems)
THEORETICAL MODELING OF NANOMATERIALS
PRECISE DESCRIPTION OF PROPERTIES
INTEREST IN SEVERAL SYSTEMS
(nanowires, molecular systems, graphene)
MÉTODOS AB INITIO
EQUAÇÕES DE KOHN-SHAM
SOLUÇÃO POR PRECEDIMENTOS AUTO-CONSISTENTES
INTERAÇÕES INTERATÔMICAS:DESCRIÇÃO QUÂNTICA
)()()(2
22
iiiieff rErrvm
função de onda eletrônica
MATERIAIS E MICROELETRÔNICA
dispositivos
eletrônicos
simulações
atomísticas
propriedades
dos materiais
processos
de crescimento
casa
DEFEITOS EXTENSOS EM SEMICONDUTORES
MOBILIDADE DE KINKS
DEFEITOS EM DISCORDÂNCIAS
SEGREGAÇÃO DE IMPUREZAS
ESTRUTURA ELETRÔNICA DE DISCORDÂNCIAS
(Justo et al, Phys. Rev. Lett. 1997)(Justo et al, Phys. Rev. Lett. 2000)(Justo et al, Appl. Phys. Lett. 2007)
TkE
odBevv
aaa discordância
energética
FE
mE
DEFEITOS PONTUAIS E DISPOSITIVOS
substrato
canal condutor
DISCORDÂNCIAS E DISPOSITIVOS
substrato
canal condutor
NANOWIRES AND NANODEVICES
SILICON NANOWIRES
PN junction sensors of molecules
(Lieber, Science 2002) (Lieber, PNAS 2005)
(Garnett, Nano Letters 2010)
photonic crystals batteries
(Cui, Nature Nanotechnology 2007)
DISPOSITIVOS DE GAP LARGO
DISPOSITIVOS DE DIAMANTE
DOPAGEM TIPO-P E TIPO-N> JUNÇÕES PN
GAP LARGO (5.5 EV)> ALTAS POTÊNCIAS E TEMPERATURAS
ALTA MOBILIDADE DE PORTADORES> ALTAS FREQUÊNCIAS
LEDS e FOTO-DETETORES NA REGIÃO DO ULTRA-VIOLETA
(Justo et al, J. Phys. Condens. Mat. , 2008)(Justo et al., Phys. Rev. B, 2009)
(Koizuimi et al., Science 2001)(Isberg et al., Science 2002)
LED de diamante
fotodetetor de diamante
)(rV
r
INTERATOMIC POTENTIALS
Expansão de muitos-corpos(termos angulares e de ordem local)
Interações Si-Si (Justo et al., Phys. Rev. B, 1997)(Justo, Handbook of Materials Modeling, 2004)
Interações Si-N (Justo et al., Phys. Rev. B ,1998)
Materiais amorfos (Justo et al, Phys. Rev. B, 2003)
612
4)(ijij
ij rrrV
N
jiijT rVE
1,)(
σ and ε: adjusted parameters repulsive atractive
Recommended