Fundamentals of Materials Science and Engineering: An Integrated Approach, 3e

GTBL042-12 GTBL042-Callister-v2 August 13, 2007 18:22

476 • Chapter 12 / Electrical Properties

Si Si Si Si

Si Si Si Si

Si Si Si Si

(a)

Si Si Si Si

Si Si

Hole

Si

Free electron

 Field

Si

Si Si Si Si

(b)

Si Si Si Si

Free electron

 Field

Si Si Si

Hole

Si

Si Si Si Si

(c)

Figure 12.11 Electron bonding model of

electrical conduction in intrinsic silicon:

(a) before excitation, (b) and (c) after

excitation (the subsequent free-electron and

hole motions in response to an external

electric field).