Question

State the conditions for the formation of Schottky defect. The following picture shows bands for materials having different electrical properties.

Classify them as semiconductors, metals and insulators with reason.

Answer 1

Conditions for the formation of Schottky defect: Ionic compounds with the following properties have a Schottky defect:

1. Strong ionic characteristics.
2. A high anion coordination number.
3. There is a slight variation in cation and anion sizes.

Classification of materials:

1. Metal is the material 'A'.
   Because the empty conduction band and filled valence band are connected.
2. Material 'B' has semiconductor properties.
   Due to the little gap that exists between the conduction and valence bands.
3. Material 'C' is an insulator.
   As a result of the larger gap between the conduction and valence bands.