Energy gap of germanium from conductivity change with temperature

[Larsson]

The conductivity of pure germanium increases by 50% when the temperature is increased from 20 degree C to 30 degree C. What is the energy gap E_g between the conduction and the valence bands of germanium?

b) For silicon E_g = 1.1eV, what is the percentage change in the conductivity for the same temperature change?

It would be nice if someone could take a few minutes to explain this.

 

[inha]

The standard procedure here is that you show what you've done so far and then you get help.

You need to relate the conductivity to the number of electrons in the conduction band as a function of temperature. That should give you a starting point.