Question

A PN- junction has a thickness of order of
A. 1 cm
B. 1 mm
C. ${{10}^{-6}}m$
D. ${{10}^{-12}}cm$

Answer 1

Inside a semiconductor, a p-n junction is an interface or a border between two semiconductor material types, namely the p-type and the n-type. The semiconductor's p-side, or positive side, has an excess of holes, whereas the n-side, or negative side, has an excess of electrons. The doping process is used to produce the p-n junction in a semiconductor. The process of doping is discussed in further depth in the next section.

Complete step by step solution:
When we utilise various semiconductor materials to produce a p-n junction, we create a grain boundary that prevents electrons from moving from one side to the other by scattering electrons and holes, which is why we employ the doping process. With the aid of this example, we will be able to comprehend the doping process. Consider a p-type silicon semiconductor sheet that is very thin. A portion of the p-type Si will be changed to n-type silicon if a tiny quantity of pentavalent impurity is added. This sheet will now have both a p-type and an n-type area, as well as a junction between the two. Diffusion and drift are the two sorts of processes that occur following the creation of a p-n junction.
As we all know, the concentration of holes and electrons on the two sides of a junction differs, with holes from the p-side diffusing to the n-side and electrons from the n-side diffusing to the p-side. This causes a diffusion current to flow across the connection. When an electron diffuses from the n-side to the p-side, it leaves an ionised donor on the n-side, which is stationary. On the n-side of the junction, a layer of positive charge develops as the process progresses. When a hole is moved from the p-side to the n-side, an ionised acceptor is left behind on the p-side, causing a layer of negative charges to develop on the p-side of the junction.
The depletion area is defined as a region of positive and negative charge on each side of the junction. An electric field direction from a positive charge to a negative charge is generated due to this positive space charge area on each side of the junction. An electron on the p-side of the junction travels to the n-side of the junction due to the electric field. The drift is the name given to this motion. We can observe that the drift current runs in the opposite direction as the diffusion current.
A PN junction is created when P-type semiconductor is combined with N-type semiconductor. There is a very tiny area, on the order of micrometres. The depletion region is the name given to this area. As a result, the thickness of the depletion zone of the PN junction is in the order of ${{10}^{-6}}m$
Hence option C is the correct answer.

Note:
The voltage applied determines one of three biassing states for the p-n junction diode.
There is no external voltage provided to the p-n junction diode while it is at zero bias.
Forward bias: The p-type is linked to the positive terminal of the voltage potential, while the n-type is connected to the negative terminal.
Reverse bias: The p-type is linked to the negative terminal of the voltage potential, while the n-type is connected to the positive terminal.