(a) What are majority and minority charge carriers of p-type and n-type semiconductors? (b) Explain briefly the formation of diffusion current and…

In p-type semiconductor:

Majority charge carriers – holes

Minority charge carriers – electrons

In n-type semiconductors:

Majority charge carriers – electrons

Minority charge carriers – holes

Diffusion current – during the formation of a p-n junction, due to the concentration gradient across p and n sides, holes diffuse from p side to n side ($\displaystyle p \rightarrow n$) and electrons diffuse from n side to p side ($\displaystyle n \rightarrow p$). This motion of charge carriers gives rise to diffusion current across the junction.

Drift current – due to the electric field at the junction, an electron on the p side of the junction moves to the n side and a hole on the n side of the junction moves to the p side. This motion of charge carriers due to the electric field gives drift current.