Write four points in distinguishing between $p$-type semiconductor and $n$-type semiconductor.

When an $n$-type semiconductor is heated,

In a semiconductor,the intrinsic carrier concentration of electrons and holes is $6 \times 10^8 \ m^{-3}$. After doping with some impurity,the electron concentration increases to $9 \times 10^{12} \ m^{-3}$. Find the new hole concentration.

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:

$P-$type semiconductor is formed when:

In the energy band diagram of a material shown in the figure,the open circles and filled circles denote holes and electrons,respectively. The material is: