Subject I 科技英语课件

This random (随机的) thermal motion causes the distance between atoms
to randomly fluctuate, slightly disrupting the perfect geometric arrangement of atoms. This imperfection, called lattice vibrations (晶格振动), affects some
electrical properties are superior to those of nonsingle-crystal
material, since grain boundaries tend to degrade the electrical characteristics.
1.3 Atomic bonding (原子价键)
An ordered region is a spatial volume (空间范围) in which atoms or
molecules have a regular geometric arrangement or periodicity. Amorphous materials have order only within a few atomic or molecular dimensions (尺度), while polycrystalline materials have a high degree of order over many atomic or molecular dimensions. These ordered regions, or single-crystal regions, vary in size and orientation with respect to one another. The single-crystal regions are called grains ( 晶 粒 ) and are separated from one another by grain boundaries (晶界).
Outline of this course
Subject I: Crystal structure of solids Subject II: Theory of solids Subject III : Translation Subject IV : Carrier transport and excess carrier phenomena
The atoms at the two extremes ( 端 ) of the periodic table ( 周期 表 ) (excepting the inert elements ( 惰性元素 )) tend to lose or gain valence electrons (价带电子), thus forming ions. These elements in group I of the periodic table tend to lose their one electron and become positively charged ( 带正电 ), while the elements in group VII tend to gain an electron and become negatively charged. These oppositely charged ions then experience ( 通 过 ) a coulomb attraction (库伦吸引) and form a bond referred to as an ionic bond (离子键).
electrical parameters of semiconductor materials.
Another type of defect is called a point defect (点缺陷). In an ideal single-crystal lattice, the atoms are arranged in a perfect periodic arrangement. However, in a real crystal, an atom may be missing from a particular lattice site. This defect is referred to (称为) as a vacancy (空位). In another situation, an atom may be located between lattice sites. This defect is referred to as an interstitial (间隙).
Subject IX: Optical devices --- Solar cell, LED
Subject X: Overview
Subject 1: Crystalline structure of solids
1.1 Semiconductor Materials
Semiconductors are a group of materials having conductivities (电导 率)between those of metals and insulators. Two general classification of semiconductors are the elemental semiconductor ( 元 素 半 导 体 ) materials, found in group IV of the periodic table (元素周期表), and the compound semiconductor (化合物
Subject V: The pn junction
Subject VI : The metal-oxide-semiconductor field-effect transistor (MOSFET) Subject VII : Device fabrication techniques Subject VIII : Efficient reading and Writing
半导体) materials, most of which are formed from combinations
(化合) of group III and group V elements.
1.2 Types of Solids
Amorphous (非晶), polycrystalline (多晶), and single crystal (单晶) are the three general types of solids. Each type is characterized by the size of an ordered region (有序化区域) within the material.
Single-crystal materials have a high degree of regular geometric
periodicity throughout the entire volume of the material. The advantage of a single-crystal material is that, in general, its
References
半导体器件导论（An Introduction to Semiconductor Devices） (Donald A. Neamen，清华大学出版社)
Photovoltaics: Devices, Systems and Applications
from University of New South Wales 科技英语语法高级教程 （西安电子科技大学出版社，秦荻辉 编著） 科技英语论文实用写作指南 （俞炳丰, 西安交通大学出版社 2003) Relative news and articles on internet
The point defects involve single atoms or single-atom locations. In forming single-crystal materials, more complex defects may occur. A line defect (线缺陷), for example, occurs when an entire row of atoms is missing from its normal lattice site. This defect is referred to as a line
covalent bond
1.4 Imperfections (缺陷) in Solids
One type of imperfection that all crystals have in common is atomic thermal vibration ( 热 振 动 ). A perfect single crystal contains atoms at particular lattice sites, the atoms separated from each other by a distance we have assumed to be constant. The atoms in crystal, however, have a certain thermal energy ( 热能 ), which is a function (函数) of temperature. The thermal energy causes the atoms to vibrate (振动) in a random manner about an equilibrium lattice point (晶格点).