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…

Explaining the formation of depletion layer and potential barrier $\displaystyle 1$+$\displaystyle 1$ Feature of junction diode for its use as rectifier $\displaystyle 1$ When an electron diffuses from n-side to p-side, it leaves behind an ionized donor on n side. Similarly when a hole diffuses from p-side to n-side, it leaves behind an ionized acceptor on p side. This space charge region consisting of immobile ions on either side of the junction is known as depletion layer. As diffusion process continues, width of depletion layer increases and consequently strength of electric field increases across the junction and thus the drift current. The potential that prevents the movement of electron from n region into p region is called potential barrier. Diode allows current to pass only when it is forward biased as resistance is small, whereas in reverse bias, its resistance is very large. Alternatively: Diode is unidirectional.