Dielectric Phenomena in Solids

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Introduction

Learning without thought is labor forgone; thought without learning is perilous.

Confucius (600 BC)

The basic distinction between a semiconductor and a dielectric (or insulator) lies in the difference in the energy band gap. At the normal ranges of temperatures and pressures, the dominant charge carriers in a semiconductor are generated mainly by thermal excitation in the bulk because the semiconductor has a small energy band gap; hence, a small amount of energy is sufficient to excite electrons from full valence band to an upper empty conduction band. In a dielectric, charge carriers are mainly injected from the electrical contacts or other external sources simply because a dielectric’s energy band gap is relatively large, ...