The valence of an impurity added to germanium crystal in order to convert it into a $P-$type semiconductor is

What are $n$-type and $p$-type semiconductors? Name the majority and minority charge carriers in each.

At a temperature of $500 \ K$,the intrinsic electron number density $(n_e)$ and hole number density $(n_h)$ in a pure semiconductor are equal to $1.5 \times 10^{16} \ m^{-3}$. Now,by adding indium impurity,the hole density $(n_h)$ increases to $4.5 \times 10^{22} \ m^{-3}$. This doped semiconductor is:

An intrinsic semiconductor is converted into $N$-type extrinsic semiconductor by doping it with

When arsenic is added as an impurity to silicon,the resulting material is

Explain $n$-type and $p$-type semiconductors based on energy band theory.