Electrical shock effect on HgCdTe photoconductive detectors

2005 
This study is concerned with electrical shock effect on performance of the n-type HgCdTe photoconductive detector with a composition of x≈0.225 in order to improve the reliability under this certain situation. Ideally, responsivity of HgCdTe photoconductive detector is proportional to its bias current. Since there are a number of thermal interfaces between the detector and the cooling reservoir, the temperature of HgCdTe chip will rise and the response will decrease with the increase of bias current. The detectors we used in the experiment were divided into two groups, one for room temperature experiment and the other for liquid nitrogen temperature experiment. A large pulse bias current was used to give the detector "an electrical shock". After the shock the resistance, responsivity and detectivity of detectors were measured at normal conditions. For the group of room temperature, the experiment results show that the detector responsivity will decrease under a 200mW pulse electric-power and the resistance will change under 400mW. When the pulse electric-power reaches 2000mW the detector will be burned out. But for the group of liquid nitrogen temperature experiment the detector responsivity will change under a 90mW pulse electric-power and the resistance will change under 290mW. A 550mW pulse electric-power will burn the detector out. Analysis with one-dimension approximation model was given, which showed that epoxy used between the interfaces was essential for increasing the reliability of HgCdTe detector.
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