# Equilibrium Distribution of Electrons and Holes

by shayaan_musta
Tags: distribution, electrons, equilibrium, holes
 P: 164 Hello. I was studying the Semiconductor and I am confused with this diagram. I have attached the diagram. Please tell me briefly what does this diagram say. So that I could ask further. I have confusion with this diagram. I don't want to be specific so that you describe the whole diagram briefly and I will try to understand it. Thank you. Attached Thumbnails
 Mentor P: 9,593 fF(E) is the probability that a state is occupied, as determined by the Fermi distribution (left=0, right=1). It is close to 0 for states of high energy (top part of the plot) and close to 1 for states of low energy (bottom). gc is the density of states in the conducting band with that specific energy - it is zero at Ec and increasing for higher energy. To find the number of electrons with a specific energy, you multiply both functions, and get the shaded area. Its area is (proportional to) the total number of electrons. gv is the same in the valence band.
 P: 164 @mfb Thank you for your kind reply. Here is another image. I am confused with a sentence "We note previously that the function f(E) for E>EF is symmetrical to .........", last four line of the first paragraph. Would you please help me in understanding how f(E) for E=Ef+dE is equal to the function 1-f(E) for E=Ef-dE. Thank you.
Mentor
P: 9,593

## Equilibrium Distribution of Electrons and Holes

I don't see another image.

Close to the Fermi energy and for small temperatures (always true in semiconductors), the function is nearly point symmetric with f(EF)=1/2 as symmetry point.
That relation is just another way to express this symmetry.
 P: 164 Here is another image. sorry friend. Now you can see the last 4 lines of the first paragraph in the given image. Thank you for your reply. Attached Thumbnails
 P: 164 Anyone help me
 Mentor P: 9,593 I don't see any open questions.
 P: 164 Hello friend. What do you mean by open question? I am asking you to clear the last four line of the first paragraph from the attached image. Thank you.
 Mentor P: 9,593 I posted an explanation in post 4.
 P: 164 I read your post several times and I got what you have said. Thank you. It is cleared now. I hope you will help me next time if I post another thread for help. Thank you.

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