I am analyzing particular type of radiation detector which is used in medical imaging device.The depletion layer and minority carrier plays a big part of the charge collection process, specially the reverse current and thickness of the depletion layer directly effect to the noise of the generated radiation signal. The reverse current is mainly generated due to minority carries in the p or n area. My question is what is the exact origin/s of minority carriers. Is it only due to thermal excitation or are there many other factors other than thermal excitation and which is more significant?
Thanks