Temperature dependence of responsivity in closely compensated extrinsic infrared detectors

Extrinsic infrared detectors which have closely compensated residual impurities shallower than the major dopant exhibit a large temperature dependence of the responsivity caused by changing occupation of these levels. A model is developed and its behavior is explored using indium-doped silicon as an example. The temperature dependence of the responsivity at low temperatures is found to be a series of plateaus for each overcompensated level. When exact compensation occurs, a unique peak of very high responsivity is predicted. The model is fitted to published Si:In detector data exhibiting such a series of plateaus and good agreement is found.