Draw a labelled energy band diagram for a solid which is an insulator. What is the main difference between this diagram and that of a semiconductor?

Explanation

This is the diagram representing an insulator.

The energy gap is small for semiconductors.
Main difference between this diagram and that of a semiconductor is that the energy gap between CB and VB in case of an insulator is about 7 eV whereas in case of a semiconductor it is 1.1 eV in case of Si and 0.7 eV in Ge.