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

$A$ silicon sample is made into a $p$-type semiconductor by doping. Indium atoms are added at a rate of one atom per $5 \times 10^7$ silicon atoms. If the number density of silicon is $5 \times 10^{28} \text{ atoms/m}^3$,calculate the number density of acceptor atoms per $\text{cm}^3$.

In a sample of pure silicon, $10^{13} \text{ atoms/cm}^3$ of phosphorus is added. If all donor atoms are active and the electron mobility is $1200 \text{ cm}^2/\text{V}\cdot\text{s}$, what will be the resistivity at $20^\circ\text{C}$ in $\Omega\cdot\text{cm}$?

$A$ crystal of intrinsic silicon at room temperature has a carrier concentration of $1.6 \times 10^{16} / m^3$. If the donor concentration level is $4.8 \times 10^{20} / m^3$, then the concentration of holes in the semiconductor is

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

For pure $Ge$,the intrinsic carrier density is $10^{19} \ m^{-3}$. If donor impurity is added with a density of $10^{23} \ m^{-3}$,what will be the hole density (in $m^{-3}$)?