two electrodes(di means two and ode means electrode).A p-n junction
diode is made up of semiconductor crystal which has two
terminals.Junction diode is formed when a semiconductor material such
as silicon or germanium is doped in such a way that one side of it
becomes a p-type and the other side as n-type then we obtain a p-n
junction diode.The plane separating is called a junction.
P-N JUNCTION-DEPLETION LAYER AND BARRIER POTENTIAL:
When p-n junction is formed,the free
electrons and the holes which are in higher concentration on n-side
diffuse over to p-side and p-side diffuse over to n-side this way the
electrons and holes combine and become neutral.This results in the
formation of a narrow region on the either side of the junction which
becomes free from mobile charge carriers.This region is called
depletion layer because the mobile charge carriers are depletion from
this region.The n-type material near the junction becomes positively
charged due to immobile donor ions and the p-type material becomes
negatively charged due to immobile acceptor ions.This creates an
electric field near the junction directed from n-region to p-region
and causes a potential barrier Vb.The potential barrier stops further
diffusion of holes and electrons across the junction.And the value of
the potential barrier depends upon the nature of the crystal,its
temperature and the amount of doping. 06:35
