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

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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