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• Current used to inject electrons into semiconducting
• Excitation and recombination result in emission of
photons with energy related to bandgap.
• Higher bandgap results in shorter wavelength – Phosphors
• Excitation by way of a-c field. Recombination Mechanisms
• Direct recombination
– is constant in time (spontaneous)
– Recombination lifetimes:
• Statistical description of this rate
Two key cases:
– Excess electrons in p-type material
– Excess holes in n-type material • In each case, the recombination lifetime is expressed in
terms of the majority carrier concentration.
terms – Bottom line: In direct recombination, majority carrier
concentrations decay at the same rate as minority
carrier Recombination Mechanisms
• Indirect recombination (trapping)
– More common than direct recombination in Si
– Involves interaction with recombination levels that
lie within the bandgap
• These levels are associated with lattice defects and
impurities in the SC
• Recombination centers must be able to receive one type of
carrier and then be able to capture the other type in order
to facilitate e-h annihilation.
• It’s a two st...
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This note was uploaded on 04/02/2014 for the course EECS 321 taught by Professor Zorman during the Spring '10 term at Case Western.
- Spring '10