Analysis of operation of a photoresistor based on CdxHg1−xTe at high bias currents

The photoresponse signal and the spectral density of the charge carrier fluctuations are calculated as functions of the frequency for a photoresistor based on n-type Cd_xHg_1–xTe at various bias currents. It is shown that when the photocarrier time of flight is shorter than their lifetime the threshold power of the photoresistor is observed to rise owing to the effect of minority carriers being extracted from the photoresistor bulk. The threshold sensitivity of the photoresistor was analyzed over a wide range of frequencies with allowance for the thermal noise at various values of the parameters of the semiconducting material of the sensitive element and recording circuits. It was found that the limitations of photoresistor circuits with a constant bias can be overcome by employing contactless switching of a cadmium mercury telluride semiconductor specimen in a microwave resonator.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 125–130, June, 1978.