- #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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SUMMARY
The discussion centers on the validity of the mass action law, \(np = n_i^2\), within the space charge region of a p-n junction diode. It is established that while this relationship holds true for an unbiased junction with no net carrier recombination or generation, many textbooks utilize the depletion approximation, which neglects carrier presence in the depletion region. The law of the junction, expressed as \(np = n_i^2 e^{qV_a/kT}\), remains applicable throughout the space charge region, reverting to the mass action law when the applied voltage \(V_a\) equals zero.
PREREQUISITES- Understanding of p-n junction diode physics
- Familiarity with semiconductor carrier concentrations
- Knowledge of the depletion approximation in semiconductor theory
- Basic principles of thermionic emission and voltage effects
- Study the implications of the depletion approximation in semiconductor devices
- Explore the law of the junction in detail, including its derivation and applications
- Investigate the effects of applied voltage on carrier concentrations in p-n junctions
- Learn about advanced semiconductor models that include carrier dynamics in the depletion region
Electrical engineers, semiconductor physicists, and students studying solid-state electronics will benefit from this discussion, particularly those focusing on the behavior of p-n junction diodes and their applications in electronic circuits.
- #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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