Question

An intrinsic semi-conductor will behave similar to an insulator at T = 0 K .Why?

Answer 1

At absolute zero (0K), an intrinsic semiconductor will behave like a perfect insulator because at this temperature, the electrons in the valence band will remain there. When the temperature increases, some of the electrons from the valence band get excited and moves to the conduction band. This will give rise to the conductivity of the semiconductor.