- #1
rkgjet
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does np=ni^2 holds even the space charge region of a pn junction diode?
Space charge region of p-n junction diode
- Thread starter rkgjet
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- Charge Diode Junction P-n junction Space
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The discussion centers on whether the mass action law, np = ni^2, holds true in the space charge region of a p-n junction diode. It is noted that for an unbiased junction without net carrier recombination or generation, this relationship is valid. However, many textbooks apply the depletion approximation, which assumes no carriers exist in the depletion region, focusing solely on ionized dopant concentrations. The law of the Junction is introduced, indicating that np = ni^2e^(qVa/kT) applies throughout the space charge region, with the mass action law being valid at zero applied voltage. Overall, the presence of carriers in the depletion region challenges traditional assumptions in semiconductor theory.
- #2
bob012345
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For an unbiased junction with no net carrier recombination or generation I believe it does however most books use the depletion approximation where they assume there are no carriers in the space charge or depletion region and only the ionized donor and acceptor dopant concentrations matter. This graph shows the carrier concentrations to not go to zero in the depletion region.
There is something called the law of the Junction which goes as ##np=n_i^2e^{qV_a/kT}## where ##V_a## is the applied voltage. This is valid throughout the space charge region. For ##V_a=0## the mass action law ##np = n_i^2## is recovered.
https://inst.eecs.berkeley.edu/~ee130/fa13/pnjunctions.pdf
There is something called the law of the Junction which goes as ##np=n_i^2e^{qV_a/kT}## where ##V_a## is the applied voltage. This is valid throughout the space charge region. For ##V_a=0## the mass action law ##np = n_i^2## is recovered.
https://inst.eecs.berkeley.edu/~ee130/fa13/pnjunctions.pdf
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