THEORETICAL MODELING OF NANOSTRUCTURED MATERIALS

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1 ESCOLA POLITÉCNICA USP THEORETICAL MODELING OF NANOSTRUCTURED MATERIALS PROF. JOÃO F. JUSTO ELECTRONIC SYSTEMS ENGINEERING DEPARTMENT

2 OUTLINE Physical properties of materials Nanoscale investigations at EPUSP Theoretical modeling of materials Properties of nanostructured materials

3 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.

4 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

5 CHALLENGES IN MICROELECTRONICS metallic contact dielectric conducting channel insulating layer substrate

6 ATOMIC ORGANIZED SYSTEMS CONDENSED SYSTEMS MOLECULAR SYSTEMS

7 ATOMISTIC SIMULATIONS INTERATOMIC INTERACTIONS EQUATIONS OF MOTION PHYSICAL PROPERTIES

8 INTERATOMIC INTERACTIONS CLASSICAL APPROACH QUANTUM APPROACH ),...,, ( 2 1 N i r r r F V ) ( ) ( ) ( ) ( i I i i i r E r r V r m

9 EQUATIONS OF MOTION MOLECULAR DYNAMICS F i m i 2 d ri 2 dt V ( r 1,..., r N ) MONTE CARLO (Metropolis) MINIMIZATION METHODS (Stepest Descent ou Conjugate Gradient)

10 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

11 DEFECTS IN SEMICODUTORS DOPANTS DEFECT ENGINEERING BENEFICIAL IONIC IMPLANTATION HYDROGENATION DETRIMENTAL PASSIVATION TERMALIZATION IONIC IMPLANTATION

12 IMPURITIES IN SEMICONDUTORS IMPURITIES IN DIAMOND, GaAs, BN GaN, SiC ENERGETICS OF IMPURITIES migration trajectory ELETRONIC AND OPTICAL PROPERTIES MAGNETISM electronic structure aa conduction band (Justo et al., Phys. Rev. B, 2009) (Justo et al., Appl. Phys. Lett., 2006) (Justo et al., Phys. Rev. B, 2011) aaaaaaaaaa valence band

13 NANOELECTRONIC DEVICES NEW GENERATION OF NANODEVICES Nanotubes Nanowires Molecules Graphene

14 SEMICONDUCTING NANOWIRES STRUCTURAL PROPERTIES OF SILICON NANOWIRES STABILITY AND PLASTICITY σ σ SCALING LAWS ELETRONIC PROPERTIES TIN OXIDE NANOWIRES (Justo et al., Phys. Rev. B 2007) (Justo et al., J. Phys. Chem. C, 2012) (Justo, in Trends in Computational Nanomechanics, 2010)

15 DIAMONDOIDS HYDROCARBON SUCESS IN SIZE SEPARATION (Dahl et al., Science 2003) fundamental building blocks (Merkle, Nanotechnology 2000) C 10 H 16 electron emission devices (Yang, Science 2007)

16 MOLECULAR CRYSTALS ADAMANTANE C 10 H 16 FUNDAMENTAL BUILDING BLOCKS MOLECULAR CRYSTALS largecohesiveenergy large bulk modulus A (Justo et al., Phys. Rev. B, 2009) (Justo et al., J. Phys. Condens. Mat., 2010)

17 NANODIAMOND: MEDICAL APPLICATIONS amantadine USED IN TREATING INFLUENZA, PARKINSON AND DEPRESSION DRUG DELIVERY C10H17N rimantadine C12H 21N M2 channel (Justo et al., J. Phys. Chem. A, 2010)

18 GROUP IV GRAPHENE graphene graphane GROUP-IV GRAPHENE (C, Si, Ge, Sn) HYDROGRNATION AND FLUORINATION ELECTRONIC BAND STRUCTURE (Justo et al, J. Phys. Chem. C, 2011)

19 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)

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21 INTERAÇÕES INTERATÔMICAS: DESCRIÇÃO QUÂNTICA MÉTODOS AB INITIO EQUAÇÕES DE KOHN-SHAM 2 2m 2 v eff ( r i ) ( ri ) E ( r ) i função de onda eletrônica i SOLUÇÃO POR PRECEDIMENTOS AUTO-CONSISTENTES

22 MATERIAIS E MICROELETRÔNICA dispositivos eletrônicos processos de crescimento propriedades dos materiais simulações atomísticas

23 DEFEITOS EXTENSOS EM SEMICONDUTORES MOBILIDADE DE KINKS aaa discordância v d v o e E k B T energética DEFEITOS EM DISCORDÂNCIAS casa E F E m 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)

24 DEFEITOS PONTUAIS E DISPOSITIVOS canal condutor substrato

25 DISCORDÂNCIAS E DISPOSITIVOS canal condutor substrato

26 NANOWIRES AND NANODEVICES PN junction sensors of molecules (Lieber, Science 2002) (Lieber, PNAS 2005) photonic crystals SILICON NANOWIRES batteries (Garnett, Nano Letters 2010) (Cui, Nature Nanotechnology 2007)

27 DISPOSITIVOS DE GAP LARGO LED de diamante DISPOSITIVOS DE DIAMANTE DOPAGEM TIPO-P E TIPO-N > JUNÇÕES PN (Koizuimi et al., Science 2001) (Isberg et al., Science 2002) GAP LARGO (5.5 EV) > ALTAS POTÊNCIAS E TEMPERATURAS fotodetetor de diamante 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)

28 INTERATOMIC POTENTIALS σ and ε: adjusted parameters repulsive atractive V (r) r V ( r Expansão de muitos-corpos (termos angulares e de ordem local) ij ) 4 rij E 12 N rij V ( T r ij i, j1 ) 6 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)