When a battery is connected to a $P$-type semiconductor with a metallic wire,the current in the semiconductor (predominantly),inside the metallic wire,and inside the battery is due to which charge carriers respectively?

What is the valency of donor impurity? Name these impurities.

When $Ge$ crystals are doped with phosphorus atoms,then it becomes

If a small amount of antimony is added to germanium crystal,

When a semiconductor is doped with donor impurity,

The number of silicon atoms per $m^{3}$ is $5 \times 10^{28}$. This is doped simultaneously with $5 \times 10^{22}$ atoms per $m^{3}$ of Arsenic and $5 \times 10^{20}$ atoms per $m^{3}$ of Indium. Calculate the number of electrons and holes. Given that $n_{i} = 1.5 \times 10^{16} \; m^{-3}$. Is the material $n$-type or $p$-type?