Properties of Photoconductive CdS Evaporated Films

Photoconductive CdS films were prepared by vacuum evaporation. Films evaporated on 200°–300°C substrate obtain good photoconductivity by subsequent baking at a range of 500°C to 650°C in air or argon. Photocurrent-illumination characteristic, photoconductive time constant, spectral response, and temperature dependence of photocurrent were measured. Films of hexagonal structure were observed by x-ray diffraction. Photocurrent-illumination characteristic and photoconductive time constant of films are not inferior to those of single crystal. The films show two types of typical spectral response, the one is that of single crystal and the other has a maximum peak at a vicinity of 580 mµ.