Question

In semiconductors, thermal collisions are responsible for taking a valence electron to the conduction band. Why does the number of conduction electrons not go on increasing with time as thermal collisions continuously take place?

Answer 1

Explanation:

this is the reason why number of conduction electrons not go on increasing

Answer 2

In semiconductors, thermal collisions are responsible for taking a valence electron to the conduction band. Additionally, in the form of heat, the energy is lost, and this is due to the carrier’s collision with atoms and other charge carriers.

Explanation:

• To the conduction band, from the valence band, an electron jumps only there is an enough energy gain. Sometimes, the thermal collisions do not offer enough energy for the electron jumping.
• Additionally, in the form of heat, the energy is lost, and this is due to the carrier’s collision with atoms and other charge carriers.
• Due to this loss, with enough energy, only few electrons are left to jump to the conduction band from the valence bond.
• Thus, the electron population in the conduction hand does not increase with time.