Question

Q) Explain the formation of depletion layer and potential barrier in a p-n junction ?

Answer 1

1)Formation of depletion layer :-
During the formation of pn junction, the difference in electrons and holes concentration established a density gradient across the p and n side.Holes from p-side moved to n-side leaving behind the negatively charge ions in the p side Similarly, the electrons from n side diffused to p side leaving behind the positively charge ions in the n-side. At the junction due to the combination of free electrons and holes, depletion of the mobile charge carrier take place at this region i.e,they become neutral.
This region where depletion of mobile charge carrier take place is known as depletion layer or region.

2)Formation of potential barriers :
The +ve and -ve charge ions on either side of the junction established a potential different across the junction. This potential different across the junction oppose the further movement of the electrons and holes across the junction. Within no time the potential different completely stopped any movement of holes and electrons and a POTENTIAL BARRIER is said to be formed.