Question

What are bands in conductors semiconductors and insulators?

Answer 1

The electronic band structure is an energy schema to describe the conductivity of conductors, insulators, and semiconductors. The schema consists of two energy bands (valence and conduction band) and the band gap


In conductors, the valence band is either not fully occupied with electrons, or the filled valence band overlaps with the empty conduction band.

In insulators the valence band is fully occupied with electrons due to the covalent bonds.

in semiconductors, there is a band gap, but compared to insulators it is so small that even at room temperature electrons from the valence band can be lifted into the conduction band.