When the temperature of a semiconductor increases,then:

What is the number density of donor atoms which must be added to a pure germanium semiconductor to make an $n$-type semiconductor of conductivity $6.4 \ \Omega^{-1} \ cm^{-1}$? The mobility of electrons in $n$-type germanium is $4 \times 10^3 \ cm^2 \ V^{-1} \ s^{-1}$. Neglect the contribution of holes to conductivity.

At room temperature,a $p$-type semiconductor has

An intrinsic semiconductor is electrically neutral. An extrinsic semiconductor having a large number of current carriers would be:

The following band-energy diagram represents:

For an intrinsic semiconductor, if $n_h$ and $n_e$ represent the number of holes per unit volume and the number of free electrons per unit volume respectively, then: