LED'S operation
Well an LED's colour is determined by the energy band of the semiconductor(GaAs). If the impurities have different energy band than the semiconductor where does the remaining energy go?
Current thru an LED produces light and heat. Light according to the band-gap and heat according to the volt*current product the same as anything that has resistance. Minuscule impurities are not significant in either of those.
ASKER
I mean that the band gap of the impurities may be different from the band gap of the GalliumArsenide. So different energy is required to drag the electron of the impurity into the conductive band.So there is a energy difference between the semiconductor band gap and the impurities band gap.
The answer is almost always "heat".
ASKER
thank you all for your participation
Even the best LED's are only 40% efficient. The "extra" energy goes into heat
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When the electron falls through the band gap a photon of wavelength equivalent to the band gap is generated. There's no "remaining energy."