$A$ semiconductor doped with a donor impurity is

In Germanium,the concentration of Aluminum is $\sim 10^{21} \text{ atoms}/m^3$. The intrinsic carrier concentration in the pure semiconductor is $\sim 10^{19} /m^3$. After adding the impurity,what is the electron concentration?

$A$ pure semiconductor has equal electron and hole concentration of $10^{16} \ m^{-3}$. Doping by gallium increases $n_{h}$ to $5 \times 10^{22} \ m^{-3}$. Then,the value of $n_{e}$ in the doped semiconductor is

When an $n$-type semiconductor is heated,

The impurity atom added to germanium to make it $N-$type semiconductor is

In $p-$type semiconductor,the majority charge carriers are