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Diode Equation and Saturation Current

  1. Sep 14, 2015 #1
    Good day all:

    For the diode equation: [tex]I(V)=I_{sat}e^{\frac{Ve}{nKT}}-I_{sat}[/tex]

    I also know that the second term in the equation is negligible if: [tex]V> > nV_{T}[/tex]

    Vt is thermal voltage
    n is ....just a factor related to the quality of the material

    I have these initial conditions:
    [tex]V> 0.1V\, \, \, ,kT\approx .025 eV\, \, \, n\approx 2[/tex]

    Its easy to show that the my inital conditions lead to a V much greater that n*thermal voltage.

    My question is: Why is the saturation Current negligible? I know it has something to do with recombination rate but can anyone give me a simple explanation? So many websites just say that the order relation is true but give no evidence as to why.
  2. jcsd
  3. Sep 14, 2015 #2


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    Staff: Mentor

  4. Sep 16, 2015 #3
    Because most of the current is in the forward direction and the reverse current, due to the minority carriers, is low. Typically in the order of nA to uA.
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