To obtain a $P$-type germanium semiconductor,it must be doped with

$P$-type semiconductor has acceptor levels $57 \, meV$ above the valence band. The maximum wavelength of light required to create a hole is (Planck's constant $h = 6.6 \times 10^{-34} \, J-s$)

Doping of a semiconductor (with small impurity atoms) generally changes the resistivity as follows.

If one indium atom is doped per $5 \times 10^7$ silicon atoms,and the number density of silicon atoms is $5 \times 10^{28} \, \text{atoms}/\text{m}^3$,find the number density of acceptor atoms in $\text{atoms}/\text{cm}^3$.

The semiconductors are generally

An $n$-type and $p$-type semiconductor can be obtained by respectively doping pure silicon with