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User defined recombination
Posted 07.06.2019, 07:32 GMT-4 Electromagnetics, Low-Frequency Electromagnetics, Semiconductor Devices 3 Replies
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I am simulatinig a simple p-n junction and I included a user defined recombination mechanism to my model. And recombination rate is given a constant number (1E26(1/m^3)). However, I observed that calculated current changes with applied bias. How could that be? Is there any specification on applied bias for user defined recombination. I was expecting a fixed current as photocurrent.
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I don't use the semiconductor module but I do know a bit about semiconductors.
Your question doesn't fully make sense. In a photodiode one has an optical generation (not recombination) RATE in units of 1/m^3sec). In the first order theory, the generation rate causes a rigid shift of the I(V) curve to negative currents, resulting in a dependence of current on voltage in forward bias and nearly constant current in reverse bias.
D.W. Greve
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thanks for unit correction. I just forgot the "sec" term in my explanation.
My question is related with reverse bias case. Order of magnitude difference is available from 0 V to -0.5 V. Is it normal? No SRH, and radiative dark current components, and the temperature is 120 K (low temperature for diffusion dominant trend).
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Offhand I can't think of a situation where what you describe would occur.
I would do the following:
- plot the simulated I(V) for -0.5 < V < 0.5 with and without light
- calculate the order of magnitude photocurrent using the textbook equations
- look at plots of electric field and/ or potential through the junction to see if they make sense
- maybe do it all again at 300 K.
After that and some thinking the explanation and/ or mistake might become clear.
D.W. Greve