How Does Temperature Affect the Conductivity of a SemiConductor?
Let’s Consider the effect of increasing the temperature on the conductivity of semiconductors.
Let's look at the factors that go into conductivity of a semiconductor and consider how each of these are affected:

sigma = ni q (me + mh)

So even though mobility decreases, the exponential increase in the number of charge carriers will dominate.

The electrical conductivity of a semiconductor will increase 
exponentially with an increase in temperature!
sigma = C e – Eg/2kT

We can graph this equation on log vs. 1/T axes to get a linear plot (as with all Arrhenius type equations):
Arrhenius plot showing linear relationship between log of the conductivity vs. 1/T. The slope of the plot is equal to -Eg/2(2.3k)

previous pageback to ENGN 45 class pagenext page