Question

Describe briefly, with the help of a diagram,the role of the two important processes involved in the formation of a pn junction.

Answer 1

The two processes are (i) Diffusion (ii) Drift 

Diffusion : Holes diffuse from p side to n side (p → n) and electrons diffuse from n side to p side (n → p)

Drift : The motion of charge carriers, due to the applied electric field (vector E) which results in drifting of holes along vector E and of electrons opposite to that of electric field (vector E).