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Homework Help: I have question,The electron and hole concentration in a intrinsic

  1. Feb 25, 2012 #1


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    I have question,
    The electron and hole concentration in a intrinsic semiconductor are n1 and p1 respectively.When doped with a p-type material these change to n and p repectively,then
    a)n+p = n1+p1
    b)n+n1= p+p1
    c)np1 = n1p
    d)np = n1p1

    could anyone explain what would be the solution.
    I am new to electronics and learning the concepts. I think the answer should be opton (b) as only electrons and holes can added before and after seperately.
  2. jcsd
  3. Feb 25, 2012 #2
    Re: semiconductors

    I think the Answer to your question should be (d).

    When you start with the subject there is an explanation that product of the concentration of holes and electrons is always equal to a constant. Thus on addition of acceptor atoms there will be additonal holes which would alter the concentration of electrons also due to recombination but the fact that product of concentration is always a constant and is given by :- (For intrinsic semiconductor, n=p=[n(i)]^2 ) this constant always remains there !
  4. Feb 25, 2012 #3


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    Re: semiconductors

    Thanks for the update
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