In a pure silicon crystal,the electron-hole concentration is $10^{16} \ m^{-3}$ at $301 \ K$. Now,$10^{21}$ atoms of phosphorus are added per cubic metre. The new hole concentration in silicon is (in per $m^3$):

$A$ $P$-type semiconductor has acceptor levels $57 \; meV$ above the valence band. The maximum wavelength of light required to create a hole is (Planck's constant $h = 6.6 \times 10^{-34} \; J \cdot s$, speed of light $c = 3 \times 10^8 \; m/s$)

$A$ $P$-type semiconductor is:

In extrinsic $P$ and $N$-type semiconductor materials,the ratio of the impurity atoms to the pure semiconductor atoms is about

If $N_h$ and $N_e$ are the numbers of holes and conduction electrons in an extrinsic semiconductor,respectively,then:

What is the conductivity of a semiconductor sample having electron concentration of $5 \times 10^{18} \, m^{-3}$,hole concentration of $5 \times 10^{19} \, m^{-3}$,electron mobility of $2.0 \, m^2 \, V^{-1} \, s^{-1}$,and hole mobility of $0.01 \, m^2 \, V^{-1} \, s^{-1}$? (Take charge of electron as $1.6 \times 10^{-19} \, C$)