Chapter 24, Problem 18STP

To determine

To explain: Holes in a semiconductor and its movement when current flow through the semiconductor.

Explanation of Solution

Introduction: Electrical conduction in semiconductors is due to movement of electrons and holes under the influence of electric field.

In a semiconductor, when an electron jumps from filled valence electron to conduction band, an electron-vacancy is created. This vacancy with effective positive charge is called a hole. The hole appears to behave as free particle with effective positive charge.

The electrical conduction in a semiconductor is due to electron-hole pair generation. The movement of electrons in the nearly empty conduction band and of holes in a nearly full valence band underthe electric field.

When current flows through a semiconductor,the holes appear to be migrating across the material in the opposite direction to the movement of free electrons.

Conclusion: The vacancy created due to movement of electrons to valence band is called a hole, which has positive charge and takes part in flow of current.