浙江大学-半导体物理基础Chapter1

浙江大学-半导体物理基础

Fall 2006

Fundamentals of Semiconductor Physics

万 歆

Zhejiang Institute of Modern Physics

xinwan@http://www.77cn.com.cn http://www.77cn.com.cn/~xinwan/

浙江大学-半导体物理基础

In memory of Prof. Xie Xide (1921-2000)

浙江大学-半导体物理基础

Chapter 1. Fundamentals

1.1 Bonds and bands 1.2 Impurities and defects 1.3 Statistical distribution of charge carriers 1.4 Charge transport

Total 12 hours.

浙江大学-半导体物理基础

Resistivity of Conductors, Semiconductors & Insulators

浙江大学-半导体物理基础

Semiconductor-forming Elements

B C Al Si N P O S

Zn Ga Ge As Se Cd In Sn Sb Te

浙江大学-半导体物理基础

Chapter 1. Fundamentals

1.1 Bonds and bands

– Crystal structures – Bond picture – Band picture

“Nearly free” electron model Tight-binding model (LCMO) k·p perturbation

1.2 Impurities and defects 1.3 Statistical distribution of charge carriers 1.4 Charge transport

浙江大学-半导体物理基础

An Apparently Easy Problem Solid

In principle, by solving Schr dinger's equation

interaction

Nuclei

Electrons

浙江大学-半导体物理基础

Lattice & Unit Cell

Crystal = periodic array of atoms Crystal structure = lattice + basis

The choice of lattice as well as its axes a,b,c is not unique. But it is

Unit cell: Parallelpiped spanned by a,b,c

usually convenient to choose with the consideration of symmetry

浙江大学-半导体物理基础

Cubic Lattices

Q: How many atoms are there in each of the

unit cells?

浙江大学-半导体物理基础

Miller Indices

浙江大学-半导体物理基础

Elemental Semiconductors

Si, Ge: 4 valence electrons

14Si:

1s22s22p63s23p2

32Ge:

[Ar]3d104s24p2

浙江大学-半导体物理基础

Covalent Bond

浙江大学-半导体物理基础

Complex Lattices

(a) Diamond: Si, Ge (b) Zinc blende: GaAs, ZnS

Interpenetrating fcc lattices

浙江大学-半导体物理基础

Wurtzite Lattice

ZnS

浙江大学-半导体物理基础

Band: An Alternative Picture

From hydrogen atom to molecule

H H

H2 antibonding bonding

浙江大学-半导体物理基础

Band Formation

N degenerate levels evolve into an energy band