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Fermi level rise up with raisng up the temperature

  1. Dec 12, 2008 #1
    Im just wondering, why the fermi level rise up with raisng up the temperature when donors are present in Extrinsic semiconductor?

  2. jcsd
  3. Dec 12, 2008 #2


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    Gold Member

    Re: semiconductors

    If I understand your question correctly, perhaps this image is of interest.

    Valence electrons in a semiconductor tend to get trapped into particular places and jump around within some type of "grid". The electrons can move around in their own little spot (and will do so with raising temperature) even though there may be a hole right beside them. Ie. they do not have enough energy to jump into the hole. Even if the electron has enough energy to jump into the hole beside it, the electron would leave a hole where the electron just jumped out of.
  4. Dec 12, 2008 #3


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    Homework Helper

    Re: semiconductors

    What does the density of states (number of states per unit energy interval) look like in the Extrinsic semiconductor? Is there a higher density of states below the fermi level?
  5. Dec 13, 2008 #4
    Re: semiconductors

    thanx for yor hekp
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