Enhancement of Photosensitivity in CdS Thin Films Incorporated by Hydrogen

Abstract

CdS films, 200 nm thick, for photoconductive sensor applications were prepared at various flow ratios on glass substrates at room temperature by radio-frequency magnetron sputtering. The sulfur concentration in CdS films crystallized at room temperature with (002) preferred orientation depends directly on the hydrogen atmosphere; the surface roughness of the films gradually increases with increasing hydrogen atmosphere. Films deposited at of exhibit an abrupt decrease of dark- and photoresistance, showing a low photosensitivity . Films deposited at a hydrogen atmosphere of exhibit a photosensitivity of , maintaining a photoresistance of an approximately . The dark- and photoresistance values of CdS films were related by a composition, surface roughness, and defect sites within the bandgap.