Question

For intrinsic semiconductors conductivity decreases with increase in temperature true or false

Answer 1

True. In an intrinsic semiconductor, the carrier concentration in the conduction band differs exponentially.

Therefore, if you keep increasing the temperature, a high number of electrons will excite to the conduction band from valence band.

Since more empty states available for electrons to get in the conduction band, you will see an increase in conductivity with the temperature.

Answer 2

The properties of an intrinsic semi conductor are as follows:

1) It is a pure semi conductor without doping.

2) Its properties will determine the charge carriers of the semi conductor.

3) The conductivity depends upon the temperature

4) When temperatures are increased the electrons absorb heat energy and hence are set in motion.

This increases the number of the conducting electrons hence increasing the conductivity.

From this we conclude that conductivity increases with increase in temperature.

The answer is hence false