Band Theory of Semiconductors
Given Below is the diagram for the Band Theory
As we can see from diagram of Band Gap of a Semiconductor, the following terms are expressed below:
- Insulators are the materials which have highest energy gap between conduction and valence band so even by applying some amount of energy electron cannot be moved from valence to conduction band so conduction of electricity is not possible in these materials according to band gap theory.
- Semiconductors are the materials which have energy gap between conductors and insulators. In this materials electrons can be moved from valence band to conduction band by applying some amount of energy. But they don’t conduct at normal conditions some energy equal to band gap between valence and conduction band need to be supplied for conductivity.
Valence Band and Conduction Band in Semiconductors
- Valence Band: It is the energy levels of valence electrons that represents the highest occupied energy band. As Compared to insulators, semiconductors have a smaller band gap, Which makes electrons in the valence band to move to the conduction band when external energy is provided.
- Conduction Band: It is situated below the valence band, consists of unoccupied energy levels and accommodates either positive charge carriers (holes) or negative charge carriers (free electrons).In semiconductors, the conduction band accepts electrons from the valence band.
As we can notice in above image that there is no band gap between conductors valence and conduction band are collapsed so in conductor materials no energy is need to be supplied to them in order to conduct.
Semiconductors
A Semiconductor is a kind of material that performs conductivity between conductors and insulators and has a conductivity value that lies between the conductor and an insulator.
In this article, we will be going through semiconductors, first, we will start our article with the introduction of the semiconductor, then we will go through holes and electrons with band gap theory, and after that we will go through properties and types of semiconductors, At last, we will conclude our article with solved examples, applications and advantages with some FAQs.
Table of Content
- Holes and Electrons
- Direct and Indirect Band Gap Semiconductors
- Properties of Semiconductor
- Types of Semiconductor
- Intrinsic Vs Extrinsic Semiconductors
- Applications of Semiconductor
- Advantages of Semiconductor
- Disadvantages of Semiconductor
- Examples of Semiconductor