Question

Find the minimum energy of electron-**** pair formation in an impurity-free semiconductor whose electric conductance increases η= 5.0 times when the temperature increases from T1 = 300 K to T2 = 400 K.

Answer 1

In a pure (intrinsic) semiconductor the conductivity is related to the temperature by the following formula very closely :

where Δε is the energy gap between the top of the valence band and the bottom of conduction band; it is also the minimum energy required for the formation of an electron-** pair. The conductivity increases with temperature and we have**