$A$ $Ge$ specimen is doped with $Al$. The concentration of acceptor atoms is $10^{21} \text{ atoms}/m^3$. Given that the intrinsic concentration of electron-hole pairs is $10^{19} /m^3$, the concentration of electrons in the specimen is:

$A$ $N-$ type semiconductor is

If $n_e$ and $v_d$ are the number density of electrons and drift velocity in a semiconductor,respectively,what happens when the temperature is increased?

Suppose a pure $Si$ crystal has $5 \times 10^{28}$ atoms $m^{-3}$. It is doped with $1 \text{ ppm}$ concentration of pentavalent $As$. Calculate the number of electrons and holes. $(n_i = 1.5 \times 10^{16} \text{ m}^{-3})$

Consider an $n$-type semiconductor in which $n_e$ and $n_h$ are the number of electrons and holes,respectively.
$(A)$ Holes are minority carriers.
$(B)$ The dopant is a pentavalent atom.
$(C)$ $n_e n_h \neq n_i^2$ (where $n_i$ is the number of electrons or holes in the semiconductor when it is in its intrinsic form).
$(D)$ $n_e n_h \geq n_i^2$.
$(E)$ The holes are not generated due to the donors.
Choose the correct answer from the options given below.

Through a semiconductor,an electric current is due to the drift of