The forbidden energy gap for germanium crystal?

In a semiconductor, the forbidden energy gap between the valence band and the conduction band is of the order is

An n-type and a p-type silicon can be obtained by doping pure silicon with

What enables Ge behave as semiconductor even though all electrons in the valence band form covalent bonds? It is due to the small width of

An N-type semiconductor is

In a good conductor, the energy levels in a valence band

Ge transistor can be operated at a temperature

What is the resistivity of a pure semiconductor at absolute zero?

In an N-type semiconductor, donor valence band is

In a P type semiconductor, the acceptor valence band is