The $n-$type semiconductors are obtained when germanium is doped with

To obtain electrons as majority charge carriers in a semiconductor,the impurity mixed is

If the ratio of electron and hole currents in a semiconductor is $\frac{7}{4}$ and the ratio of drift velocities of electrons and holes is $\frac{5}{4}$, then the ratio of concentrations of electrons and holes will be

Let ${n_h}$ and ${n_e}$ be the number of holes and conduction electrons respectively in a semiconductor. Then

For extrinsic semiconductors,when the doping level is increased:

In a $P$-type semiconductor, the acceptor energy level $E_A$ is located $57 \, meV$ above the valence band. The maximum wavelength required to create a hole is ....... $\mathring{A}$. (Given: $h = 6.6 \times 10^{-34} \, J \, s$, $c = 3 \times 10^8 \, m/s$, $1 \, eV = 1.6 \times 10^{-19} \, J$)