Photoconductive CdS films by a chemical bath deposition process

Abstract

A new technique for the preparation of CdS thin films by chemical bathdeposition is described. The CdS films prepared by this method have many ofthe advantages of those made by the spray deposition method, such as theease of coating large areas and simplicity of the process. The stoichiometry iseasy to maintain in both these methods. The films are formed on rotating substratesfrom a bath containing cadmium salt in a complex form. Electrical,photoconducting, and optical properties such as I-V characteristics, decayof photoconductivity, spectral response of photoconductivity, and optical absorptionwere studied. Addition of cations like Ag, Cu, In, and Zn to thedeposition bath makes the films amorphous. Such amorphous layers have adensity of state of the order of 10¹⁹−10²⁰/cm³/eV near the Fermi level, asdetermined by photodecay and field effect measurements. The films producedare strong, adhering tightly to the substrates, show little or no degradation,and are photosensitive as deposited.