Question

What does band gap mean?

Answer 1

1. The electrons in the same orbit exhibit different energy levels. The grouping of these different energy levels is known as the energy band.
2. There are three types of bands:
   2.1 Valance band: The energy band that consists of valence electrons' energy levels, is known as the valence band.
   2.2 Conduction band: The energy band that consists of free electrons energy levels, is known as the conduction band.
   2.3 Forbidden energy gap: The energy gap between the valence band and the conduction band is known as the forbidden band which is also known as the forbidden gap.
3. The energy difference between the valance band and the conduction band is known as the band gap.
4. Due to the band gap materials can be divided into three parts:
   4.1 Conductor: The valence band and the conduction band are overlapped in the case of the conductor.
   4.2 Semiconductor: There is a small band gap between the valence band and the conduction band in the case of semiconductors.
   4.3 Insulator: There is a large band gap between the valence band and the conduction band in the case of insulators.