Chapter 7, Problem 63E

Interpretation Introduction

Interpretation:

Band gap is an important factor for deciding conduction behavior of solid. On the basis of band gap, there are three types of solid as insulator, semiconductor and conductor.

Concept introduction:

Band gap in conductor:

The band gap in the case of metal is very small. That is almost zero. Due to this a large no of electron becomes available in conduction band and conduct electricity without much resistance.

Band gap in insulator:

The band gap in the case of insulators is much larger than $3\text{ e v}$, so that valence electron can’t jump into conduction band at room temperature. There is no electron in conduction band so conduction of electricity is not possible. That is why insulators can’t conduct electricity.

Band gap in semiconductor:

In this band gap is a finite value but smaller than $3\text{ ev }$. Because of the smaller band gap, at room temperature some electrons from valence band can jump to conduction band at room temperature, these no of electron is small and increases with in increases in temperature. That is why semiconductor behaviors between insulator and conductors and conductivity increase with temperature.

To determine: the solid would you expect to have little or no band gap

$\left(a\right)\text{ Zn}\left(s\right)\left(b\right)\text{ Si}\left(s\right)\left(c\right)\text{As}\left(s\right)$