Chapter 20.2, Problem 20.2.2PE

(a)

Interpretation Introduction

Interpretation: The band that is the valence band should be determined.

Concept Introduction:The band that forms from bonding molecular orbital in a semiconductor is called the valence band

(b)

Interpretation Introduction

Interpretation: The band that is the conduction band should be determined.

Concept Introduction: The band that forms from anti-bonding molecular orbital in a semiconductor is called the conduction band.

(c)

Interpretation Introduction

Interpretation: The region of the diagram that represents the band gap should be determined.

Concept Introduction: The band gap is the gap between the valence band and conduction band.

(d)

Interpretation Introduction

Interpretation: The band that consists of bonding molecular orbital should be determined.

Concept Introduction:The band that forms from bonding molecular orbital in a semiconductor is called the valence band that contains bonding molecular orbital

(e)

Interpretation Introduction

Interpretation: The type of semiconductor represented by the diagram should be explained.

Concept Introduction:An n-type semiconductor is one in which the dopant element has more number of valence electrons than the host element and this leads to an increase in number of negatively charged electrons in the conduction band that can move easily. So, in an n-type semiconductor conduction band is not completely empty.

A p-type semiconductor is one in which the dopant element has less number of valence electrons than the host element and this leads to electron vacancies, known as holes, in the valence band. Thus in a p-type semiconductor the valence band has electron vacancies and is not completely filled with electrons.

(f)

Interpretation Introduction

Interpretation: The elements that could be dopant from the given elements $\text{Ga}$ , $\text{Si}$ or $\text{P}$ , if the semiconductor is germanium should be determined.

Concept Introduction:The doped semiconductor given in the diagram is a p-type semiconductor. It means the dopant element must have less valence electron than germanium.