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Leakage current in diode

  1. Apr 13, 2010 #1
    My question is related to the leakage current occuring in a diode when connected in reverse bias mode. When the diode is forward biased, the source voltage first neutralizes the barrier potential and then the flow of current occurs. However, I am not able to understand how the current due minority charges flow through a diode when it is reerse bias.
    I would be very grateful if there is someone who can help me with this confusion.
  2. jcsd
  3. Apr 14, 2010 #2
    In reverse, electron-hole pairs are being thermally generated just as in the forward case. For every electron removed from its parent atom, a hole is generated as well. The electrons move when reverse biased, and they encounter holes due to p-type doping. The thermally generated electrons & holes are equal in number, but doping a semiconductor with p-type impurites, i.e. acceptors, results in low electron mobility. The electrons recombine with the abundant holes and few make it to the junction barrier. Likewise, on the n-side, an excess of electrons occur due to doping, and holes have low mobility.

    It's all about mobility of e- & h+ which varies with doping level and whether the semiconductor material is n-type, p-type, or intrinsic.

    Last edited: Apr 14, 2010
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