Reversible photoinduced changes of electronic transport in narrow-gap amorphous Sb2S3

Decreases in both dark conductivity and photoconductivity after intense and prolonged photoirradiation have been observed in the narrow-band-gap amorp hous Sb2Se3; they are similar to those observed in hydrogenated amorphous s ilicon (a-Si:H) (the Staebler-Wronski effect). The ac conductivity, on the other hand, decreases after illumination, which is in contrast to that obse rved in a-Si:H. Unlike a-Si:H, these photoinduced changes are not interpret ed in terms of light-induced defect creation. The broadening of energy leve ls of preexisting thermal-equilibrium defects by illumination could produce all of these photoinduced changes in the present system. [S0163-1829(99)14 203-6].