PHOTOINDUCED METASTABLE DEFECTS IN AMORPHOUS-SEMICONDUCTORS - COMMUNALITY BETWEEN HYDROGENATED AMORPHOUS-SILICON AND CHALCOGENIDES

The time dependent decrease in photocurrent I-p during illumination has been measured as a function of illumination intensity G and temperature T in hydrogenated amorphous silicon (a-Si:H) and amorphous As2S3 (a-As-23). It is found that I-p can be proportional to 1/[1-gamma exp{-(t/tau)(alpha)}], where gamma is a measure of the induced density of metastable defects, tau the effective relaxation time, and a the dispersion parameter. The behavior of these parameters for both material. systems are almost the same, suggesting that common kinetics dominate light induced metastable defect (LIMD) creation. A microscopic model is presented to explain common features between two entirely different categories of materials.