If the ratio of the concentration of electrons to that of holes in a semiconductor is $\frac{7}{5}$ and the ratio of currents is $\frac{7}{4}$,then what is the ratio of their drift velocities?

In a $P$-type semiconductor,the acceptor energy levels $E_A$ are located:

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:

If $N_A$ is the number density of acceptor atoms added and $N_D$ is the number density of donor atoms added to a semiconductor,and $n_e$ and $n_h$ are the number density of electrons and holes in it,then:

In an intrinsic semiconductor at room temperature,the number of electrons and holes are:

$A$ $P-$ type semiconductor can be obtained by adding