Equilibrium Distribution of Electrons and Holes

  1. 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 Files:

  2. jcsd
  3. mfb

    Staff: Mentor

    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.
  4. @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.
  5. mfb

    Staff: Mentor

    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.
  6. 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 Files:

  7. Anyone help me
  8. mfb

    Staff: Mentor

    I don't see any open questions.
  9. 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.
  10. mfb

    Staff: Mentor

    I posted an explanation in post 4.
  11. 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.
Know someone interested in this topic? Share this thead via email, Google+, Twitter, or Facebook

Have something to add?