DRIFT CURRENT :-
Drift current is the electric current, or movement of charge carriers, which is due to the applied electric field, often stated as the electromotive force over a given distance.
DIFFUSION CURRENT:-
Diffusion current is a current in a semiconductor caused by the diffusion of charge carriers. This is the current which is due to the transport of charges occurring because of nonuniform concentration of charged particles in a semiconductor.
P-N JUNCTION:-
A diode is a PN junction with p-type on one side and n-type on the other. When a positive voltage is applied to the p-type side , it shrinks and overcomes the depletion zone, causing the current flow from the p-type to the n-type side.
NUMERICAL:-
Given Data :-σ=4×10(−4)mho/m,μe=0.14m2/V−sec,μh=0.04m2/V−S
Formula :- σi=ni(μe+μh).e
Calculations :- ni=σi/((μe+μh).e)
=(4×10(−4))/(1.6×10(−19)(0.14+0.040))
ni=1.388×1016/m3
Answer :- carrier concentration = 1.388×1016/m3