Question

What is meant by energy bands in solids? How do we classify solids as conductors,

semiconductors and insulators on the basis of energy bands? Illustrate your point with

the help of their energy band diagrams.​

Answer 1

Answer:

An energy band is a range of electron energy in a solid so dense with electron states that it appears to be continuous. The number of states is finite and countable but the spacing in energy between states is miniscule. The number of discrete states in a band is on the order of the number of electrons in the solid

In insulators the electrons in the valence band are separated by a large gap from the conduction band, in conductors like metals the valence band overlaps the conduction band, and in semiconductors there is a small enough gap between the valence and conduction bands that thermal or other excitations can bridge the gap.