8 \6 A8 n2 j/ B4 a1 g% |
CHAPTER TEN / C" `9 r. [6 P. d/ i- i7 ISEMICONDUCTOR PHYSICS 2 ?" x0 Z) s: K& I. j" ~# z4 vIn this chapter, a brief description of the basic concepts governing the flow of [size=9.96001pt]current in a pn junction are discussed. Both intrinsic and extrinsic semicon$ u8 q7 G, H) q# t7 Y
ductors are discussed. The characteristics of depletion and diffusion capaci[size=9.96001pt]tance are explored through the use of example problems solved with 6 r% ^% l/ |/ a9 W, nMATLAB. The effect of doping concentration on the breakdown voltage of[size=9.96001pt]pn junctions is examined.2 y# N& ]( K% F5 _ s8 q
10.1 INTRINSIC SEMICONDUCTORS 1 ~0 o8 k- R# X6 [' y: G* D
10.1.1 Energy bands * F0 b4 V$ ]" M) f5 e! oAccording to the planetary model of an isolated atom, the nucleus that con[size=9.96001pt]tains protons and neutrons constitutes most of the mass of the atom. Electrons" }4 X+ g2 c$ s# l" I
surround the nucleus in specific orbits. The electrons are negatively charged[size=9.96001pt]and the nucleus is positively charged. If an electron absorbs energy (in the : I8 |* v& R/ b% Tform of a photon), it moves to orbits further from the nucleus. An electron[size=9.96001pt]transition from a higher energy orbit to a lower energy orbit emits a photon for ! _- q$ |8 g5 j1 F5 l+ L# Ya direct band gap semiconductor. - U. y0 v4 R0 I6 ^The energy levels of the outer electrons form energy bands. In insulators, the[size=9.96001pt]lower energy band (valence band) is completely filled and the next energy - i/ E; W: |" M5 H& W% d- mband (conduction band) is completely empty. The valence and conduction[size=9.96001pt]bands are separated by a forbidden energy gap. " n5 D) L5 l# a, `: X. C' M; r $ O' ~5 D% z: Z3 `[size=9.96001pt] 0 }$ A0 e* l+ [, u# n" X1 G9 u6 ^3 b
( F& _0 Y+ A! C9 ~9 E0 Y T 作者: llbnmo 时间: 2020-5-19 13:15
谢谢分享
