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How to identify if a semiconductor is n-type or p-type?

  1. May 12, 2014 #1
    please see attached image for problem



    if a dopant gives an electron it's an n-type, if a dopant takes an electron it's a p-type.



    i cant see how to relate the hall coefficient value to the property of being a n-type or p-type semiconductor?

    any pointers on this would really be appreciated, thanks
     

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  3. May 12, 2014 #2

    mfb

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    Staff: Mentor

    Electrons flowing in one direction will get deflected in the same direction as holes flowing in the opposite direction - for one doping type you get negative electrons at one side, for the other doping type you get positive holes at this side. This leads to a different hall coefficient.
     
  4. May 12, 2014 #3
    The Hall Coefficient is:
    RH = [itex]\frac{1}{nq}[/itex]​
    For electrons, q= -e, and our hall coefficient is:
    RH = [itex]\frac{-1}{ne}[/itex]​
    Therefore we know that n-type semiconductors have negative RH.
     
  5. May 13, 2014 #4
    hm so simple, many thanks!
     
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