Which of the following when added as an impurity into silicon produces $n-$type semiconductor?

Which of the following energy band diagrams shows the $N-$ type semiconductor?

For a $p-$type semiconductor,which of the following statements is true?

The hole and the free electron concentrations in a pure silicon at room temperature are given by $1.4 \times 10^{16} \ m^{-3}$ each under equilibrium. When it is doped with indium and the hole concentration is $n_{h} = 4 \times 10^{22} \ m^{-3}$,the electron concentration is

$N-$ type semiconductors are obtained when germanium is doped with:

Pure $Si$ at $500\, K$ has equal number of electron $(n_e)$ and hole $(n_h)$ concentrations of $1.5 \times 10^{16}\, m^{-3}$. Doping by indium increases $n_h$ to $4.5 \times 10^{22}\, m^{-3}$. The doped semiconductor is of