The current induced when the electrons diffuse from n-side to p-side and holes diffuse from p-side to n-side in the pn junction due to concentration gradient is called diffusion current.

There is a movement of minority charge carriers of p-side and n-side from p 🡪 n and n 🡪 p due to the electric field of charges of depletion region. This motion of charge carriers due to electric field is known as drift current.