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Electrical Properties of Materials ( 전기물성 )

Electrical Properties of Materials ( 전기물성 ). Prof. Kil-Sou Kim kks2072 @hanmail.net , 010-2476-2072 School of Engineering Chungbuk National University http ://www.cbucc.com 2013/9/1. Chapt . 1 Atoms and Aggregates of Atoms. Atoms and Aggregates of Atoms.

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Electrical Properties of Materials ( 전기물성 )

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  1. Electrical Properties of Materials(전기물성) Prof. Kil-Sou Kim kks2072@hanmail.net, 010-2476-2072 School of Engineering Chungbuk National University http://www.cbucc.com 2013/9/1

  2. Chapt. 1 Atoms and Aggregates of Atoms

  3. Atoms and Aggregates of Atoms • The hydrogen atom according to the old and new quantum mechanics • Nomenclature pertaining to electronic states • The electron configuration of atoms • The nature of the chemical bond and the classification of solids • Atomic arrangements in solids • Crystal structure and lattice defects

  4. 원자/많은 실험결과 양자(proton),전자(electron),중성자(neutron)로 구성,중성 전기적 중성,전자수=양자수=원자번호 전자 전하량 e=1.6*10-19[C] 전자 m= 9.107*10-31[kg] 양자 m=1.672*10-27[kg] 원자크기 Ao 10-10[m] order 핵(nucleus)크기 10-15m order 원자 묘사; empty (classical) continuous charge distribution (전자,wave mechanical) Hydrogen atom (Bohr’s model) 힘의 평형(쿨롬인력=원심력) -W (-energy)의미 Unstable model Bohr postulated a quantum number condition Hydrogen Atom -e +e =

  5. Quantum number condition Circular orbits are stable for which the angular momentum is equal to an integer times h(Planck’s const)=6.62*10-34 J sec n=1,2,3… Frequency condition Transition of the electron from Wn1 to Wn2is associated with emission and absorption of electromagnetic radiation of a frequency n Spectrum of hydrogen

  6. 광의 입자성에 대한 예 광전효과;한계파장(진동수) Compton 효과 기타 물질의 파동성에 대한 예 Tunnel 효과 Electron wave 회절, 간섭 기타 Particle or wave ? • Particle or wave ? 계의 크기 l(=h/p) • Wave mechanics, quantum mechanics 태동 • 미시입자의 거동; 고전역학(뉴턴역학)이 아닌 파동역학으로 기술 • Schrodinger wave equation ; • ;probability, charge distribution • * de Broglie 관계

  7. Electronic state(전자상태) • l=0, 1, 2, 3, 4 … • s p d f g …-state • n=1, 2, 3, 4, 5…. • K L M N O -shell • 주양자수 n일 때 총 상태수 • 파동방정식의 해(파동함수)는 다음의 특정 정수 조합에서 존재 • 주양자수; n=1, 2, 3, … • 각운동량양자수;l= 0,1,...(n-1) • 자기양자수;ml=l,(l-1),..0…-(l-1),-l • Wave function

  8. Electron configuration of atoms and periodic table of elements • Pauli exclusion principle • A given quantum state determined by three quantum numbers n,l,ml can be occupied by not more than two electrons • Chemical properties of atoms are determined mainly by the outer electron configuration • - Transition elements • - Alkali metal • - Halogen group • - Rare gas

  9. The nature of the chemical bond and the classification of solids • Type of chemical bond • Ionic crystals(NaCl, KF, alkali halide) • Valence crystals(diamond,Si,Ge,SiC) • Metals(Cu,Ag,Fe) • van der Waals crystals(solid argon, organic crystals) • 대부분의 결합이 4유형으로 엄격히 구분되는 것은 아니고 중간유형 또는 환경에 따라서도 달라짐 r -W(r0)

  10. Ionic bond

  11. Covalent bond

  12. 가전자의 공유로 왜 에너지가 저하 하는가? (양자역학적 이해)

  13. CH4, sp3, sigma bond

  14. 2(sp2+p)

  15. Metallic bond Spatial distribution of an electron in a metallic solid

  16. Electrons and nuclei in a metal • 가전자를 모든 원자핵(양이온)과 공유 • 공유결합과 같은 점, 다른 점(4족에서 공유결합/금속diamond, Si, Ge, Pb) • 도체

  17. van der Waals bond A van der Waals bond in polar molecules • van der Waals force ; dipole-dipole, quadruple-quadruple, dipole-quadruple간의 힘 • van der Waals force에 의한 결합, 매우 약한 결합

  18. diamond 반데발스 이온

  19. Atomic arrangements in solids • Crystalline, single crystal, polycrystalline • Semi-crystalline • Amorphous • Perfect crystal • Lattice defect (lattice imperfection) • - vacancy, interstitial atom, impurities, grain boundary, dislocation

  20. Crystal Structures A three-dimensional lattice showing translational symmetries 결정 : 원자나 이온이 주기적으로 배열된 고체 원자나 이온 사이에 일정한 간격이 있고 결정방향으로 병진 시키면 같은 원자나 이온이 다시 나타남

  21. Fourteen Bravais lattices

  22. Crystal Structures Cubic FeS2, iron sulfide, or pyrite, crystals. The crystals look brass-like yellow (“fool’s gold”). |SOURCE: Photo by SOK Galena is lead sulfide, PbS, and has a cubic crystal structure |SOURCE: Photo by SOK

  23. The Hexagonal Close Packed (HCP) Crystal Structure. (a) The Hexagonal Close Packed (HCP) Structure. A collection of many Zn atoms. Color difference distinguishes layers (stacks). (b) The stacking sequence of closely packed layers is ABAB (c) A unit cell with reduced spheres (d) The smallest unit cell with reduced spheres.

  25. Silicon A silicon ingot is a single crystal of Si. Within the bulk of the crystal, the atoms are arranged on a well-defined periodical lattice. The crystal structure is that of diamond. |Courtesy of MEMC, Electronic Materials Inc.

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