PHOTOCONDUCTIVE GENERATION MECHANISM AND GAIN IN INTERNAL PHOTOEMISSION INFRARED DETECTORS

The photoconductivity generation mechanism and photoconductive gain in internal photoemission infrared detectors have been studied. A simple model is proposed and it shows that the photoconductive gain of inter nal photoemission detectors is less than but close to unity and indepe ndent of the number of the emitter layers, while the current responsiv ity is proportional to the number of emitter layers. The results, in g ood agreement with the experiments, are contrary to those of quantum-w ell photodetectors due to the different photocarrier generation mechan isms between the quantum-well photodetectors and internal photoemissio n detectors. (C) 1998 American Institute of Physics. [S0021-8979(98)00 907-4].