Development of a photosensor based on photo dielectric effect of cadmium sulphide

Abstract

A photosensor is an electronic component that detects the presence of visible light, infrared radiation, and/ or ultraviolet radiation. A photosensor which changes its electrical capacitance in the presence of visible light was developed based on the photo-dielectric effect of Cadmium Sulphide (CdS). A thin layer of CdS was deposited on Fluorine-doped Tin Oxide glass using chemical bath deposition technique. The optimum photo-dielectric behaviour was observed for chemical bath temperature between 40-45 ºC. After annealing the deposited film at 180-200 ºC, they have shown a band gap in the range of 2.30– 2.40 eV. Photo-capacitance and photoconductivity in dark and visible light illumination showed a significant change, indicating these films are suitable for photo sensing applications.