List of top Physics Questions on Semiconductor

Explain the process of formation of 'depletion layer' and 'potential barrier' in a p-n junction region of a diode, with the help of a suitable diagram. Which feature of junction diode makes it suitable for its use as a rectifier?

Draw energy band diagrams of n-type and p-type semiconductors at temperature \( T>0 \, \text{K} \). Show the donor/acceptor energy levels with the order of difference of their energies from the bands.

Assertion (A): We cannot form a p-n junction diode by taking a slab of a p-type semiconductor and physically joining it to another slab of an n-type semiconductor.
Reason (R): In a p-type semiconductor \( \eta_e \gg \eta_h \) while in an n-type semiconductor \( \eta_h \gg \eta_e \).

When a p-n junction diode is forward biased:

The upper level of valence band and lower level of conduction band overlap in the case of

Draw the circuit diagram of a p-n junction diode in
(i) forward biasing and
(ii) reverse biasing.
Also, draw its I-V characteristics in the two cases.

At a given temperature, the number of intrinsic charge carriers in a semiconductor is \( 2.0 \times 10^{10} \) cm\(^{-3}\). It is doped with pentavalent impurity atoms. As a result, the number of holes in it becomes \( 8 \times 10^3 \) cm\(^{-3}\). The number of electrons in the semiconductor is:

During the formation of a p-n junction:

Initially, during the formation of a p-n junction:

When Ge is doped with a pentavalent impurity, the energy required to free the weakly bound electron from the dopant is about:

Assertion (A): The temperature coefficient of resistance is positive for metals and negative for p-type semiconductors.
Reason (R): The charge carriers in metals are negatively charged, whereas the majority charge carriers in p-type semiconductors are positively charged.

Depletion region in an unbiased semiconductor diode is a region consisting of