a
For Ge, \(E _{ g }=0.7\,eV =0.7 \times 1.6 \times 10^{-19}\,J =1.12 \times 10^{-19}\,J\). Germanium in the crystalline form has an energy gap between the valence band and conduction band. However, the pure intrinsic semiconductor can be converted into the ptype and \(n-\)type semiconductor.Trivalent impurities if added to germanium then it forms the \(p-\) type semiconductor whereas if pentavalent impurities are added then it forms the \(n-\) type semiconductor.