Photosensitivity degradation mechanism in CdS:Cu single crystals

Possible reasons of the photorcurrent decrease under illumination are discussed by comparison of all experimental data obtained in the previous studies of the photosensitivity degradation in CdS:Cu single crystals. By further studies a photosensitivity decrease is found to be due to vanishing of the shallow donors which compensate the r‐centres. A degradation mechanism consisting in transformation of the shallow donors into rapid recombination s‐centres, due to their association, is suggested. On heating in darkness these s‐centres dissociate to recover both, the initial density of the shallow donors and the high photosensitivity.