[SOLVED] urgent: effect of light on IV characteristic of pn junctions ^ ^;; Last resort time, needs to be answered by 4pm today. (18/01/08) It's a pretty qualitative question, and if possible I'd like a qualitative answer. The reason for this is that this is only a weekly experiment I've performed and while I now need to write an essay on it, I haven't actually been taught that much of the theory - so as few equations as possible please. I've been asked to investigate pn junctions, and one of the experiments involves the effect of light on the IV characteristic. From what I know, I would've expected this to produce electron hole pairs resulting in an increased leakage current in the reverse bias direction, and this is indeed what I saw experimentally. However I also expected that it would increase the number of charge carriers in the forward bias direction, leading to a steepening of the curve corresponding to higher currents at all voltages. The trouble is that instead, there was a small translation to the right, meaning negative currents for forward bias voltages, and overall a lower current at any given voltage. What's going on here??