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Equilibrium Distribution of Electrons and Holes 
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#1
Feb913, 01:53 PM

P: 184

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. 


#2
Feb913, 02:18 PM

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P: 12,113

f_{F}(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).
g_{c} is the density of states in the conducting band with that specific energy  it is zero at E_{c} 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. g_{v} is the same in the valence band. 


#3
Feb1013, 01:57 AM

P: 184

@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 1f(E) for E=EfdE. Thank you. 


#4
Feb1013, 07:27 AM

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P: 12,113

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(E_{F})=1/2 as symmetry point. That relation is just another way to express this symmetry. 


#5
Feb1013, 10:16 AM

P: 184

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. 


#6
Feb1213, 04:52 AM

P: 184

Anyone help me



#7
Feb1213, 09:41 AM

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P: 12,113

I don't see any open questions.



#8
Feb1213, 01:30 PM

P: 184

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. 


#9
Feb1213, 03:02 PM

Mentor
P: 12,113

I posted an explanation in post 4.



#10
Feb1313, 07:19 AM

P: 184

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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