The most commonly used material for making transistors is

Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If,for an $n$-type semiconductor,the density of electrons is $10^{19} \ m^{-3}$ and their mobility is $1.6 \ m^2/(V \cdot s)$,then the resistivity of the semiconductor (since it is an $n$-type semiconductor,the contribution of holes is ignored) is close to ................ $\Omega \cdot m$.

The temperature $(T)$ dependence of resistivity $(\rho)$ of a semiconductor is represented by

An $N-$type and $P-$type silicon can be obtained by doping pure silicon with

To a germanium sample,traces of gallium are added as an impurity. The resultant sample would behave like

$A$ 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