Dark noise of Ga0.47 In0.53As photoconductive detectors

We have studied the dark noise of planar, interdigitated Ga0.47In0.53As photoconductive detectors by measuring the statistical distribution of the dark current under DC bias. The measurements reveal two interesting results: (i) the probability distribution of the dark current around its DC level is Gaussian and (ii) the standard deviation of the probability distribution grows exponentially with increasing bias voltage. Utilising these data an optimum bias level was calculated to maximise the receiver sensitivity of the detector.