Zinc selenide (ZnSe), zinc sulphide (ZnS) and lead sulphide (PbS) thin films were prepared by chemical bath deposition (CBD) method. In this paper we report results on the photoconductivity behaviour of ZnSe, ZnS and PbS thin films. Photoconductivity measurements were carried out at room temperature by connecting it in series with a picoammeter (Keithley 480) and a dc power supply. Photoconductivity processes may be the most suitable technique for obtaining information about the states in the gap. The thin films showed a significance rise in photocurrent over dark current. The photoconductive studies reveal the positive photoconductive nature of the thin films. Photoconduction includes generation and recombination of carriers and their transport to the electrodes.
Key words: Thin films, photoconductivity, ZnSe, ZnS, PbS.