Decreases in both dark conductivity and photoconductivity, after intense and prolonged photo-irradiation, were observed in the narrow-bandgap amorphous material. These were similar to those observed in hydrogenated amorphous Si (Staebler-Wronski effect). On the other hand, the alternating-current conductivity decreased after illumination; unlike the case of amorphous hydrogenated Si. The photo-induced changes were not interpreted in terms of light-induced defect creation. It was concluded that broadening of the energy levels of pre-existing thermal-equilibrium defects by illumination could produce all of the photo-induced changes in the present system.

Reversible photoinduced changes in electronic transport in narrow-gap amorphous Sb2Se3 T.Aoki, H.Shimada, N.Hirao, N.Yoshida, K.Shimakawa, S.R.Elliott: Physical Review B, 1999, 59[3], 1579-81