Classification of Materials

CLASSIFICATION OF MATERIALS

The materials are classified based on their conducting property. Energy band theory can be used to explain the classification of materials.

1 Conductors

Conductor is materials that easily conducts or pass the current. There are plenty of free electrons available for electric conduction. In terms of energy band theory, the conductors have overlapping of valence band and conductive band.

Example: Copper, Aluminum, iron, etc

Properties:     1. It is rigid, non directional and crystalline in nature.

2. Conductivity is good.

3. Low melting and boiling temperatures.

2 Semiconductors

Semiconductor is a material with partially filled conduction band and valence band. The current in the semiconductor is due to the movement of electrons and holes. As the temperature increases the conduction increases.

Example: Silicon, Germanium, etc.

Properties: 1. It is rigid, directional and crystalline in nature.

2. Conductivity can be increased if proper doping material is added.

3. Low melting and boiling temperatures.

2 Insulators

In the case of insulators, the valence electrons are very tightly bound to their parent atom. The valence band and conduction band are separated by a large forbidden energy gap. The insulators have full valence band and an empty conduction band.

Example: Paper, Mica. Sodium chloride, etc.

Properties: 1. It is rigid, Unidirectional and crystalline in nature.

2. Conductivity is poor in the solid form.

3. High melting and boiling temperatures.

Energy band structure

Comparison of Conductors,Semiconductors and Insulators