P-n junction, PLEASE HELP

[Lekshmy]

Hi,

In the band diagram for the depletion region it is seen that the intrinsic level coincides with the Fermi level in the middle of the depletion region. Does this mean that the depletion region is intrinsic at the middle?

Also the Fermi level is closer to the valence band edge in the depletion region near the p side and it gradually moves away from valance band and goes closer to the conduction band edge as we approach the n side of depletion region . Does this mean that a concentration gradient is existing in the depletion region?






I am highly confused with the basic concepts of p-n junction, PLEASE REPLY TO THIS POST, It would be really helpful.

Regards,
Lekshmy

 

[errakeshpillai]

The band Diagram is a representation of the different energy levels in any structure. On the P-side the no. of holes are greater, which results in increased energy above fermi level. While on the N-side the increase in electrons causes the energy level to decrease below Fermi level..
So its the energy that is changing not the concentration..