PN junction
Introduction
Junction Dio is two terminal electric device which consist of PN formed over a semiconducting material .
The symbol of PN junction is as
The P region is referred to as anode and N region is referred to as cathode.
Formation of PN junction
Pm junction is two terminal semiconductor device which consist of PN junction formed over a semiconducting material.
PN junction is formed when two extrinsic semiconductor (one P type and another N type) are dropped into a semiconducting material such as silicon or germanium.
The formation of PN junction
During the formation of PN junction the free electron from N region diffuses into P region to combine with hole. This combination of hole with free electron creates are negative potential that is negative charge career at P side near the junction. Similarly the holes of P region diffuses into N region and combine with electron this combination of free electron with holes and creates a positive potential at N side near the junction. So there exists a region formed near the junction having a immobile charge carrier this region is known as depletion region or depletion layer.
The depletion layer act as a barrier and prevent further motion of charge carrier.
The potential difference possessed by the depletion layer and PN junction is known as barrier potential.
The the thickness of depletion region is of order of microns.
