Effect of wavelengths on the structure, morphology and optoelectronic properties of cadmium sulfide thin films by laser assisted chemical bath deposition

Abstract

Laser assisted chemical bath deposition (LACBD) is an interesting technique to synthesize semiconductor thin films. The effects of three laser wavelengths (445, 457 and 532 nm) on the structure, composition, morphology and optoelectronic properties of cadmium sulfide (CdS) thin films by LACBD are presented. Structural analysis of the thin films confirmed their polycrystalline nature. The surface composition specifics and chemical states of Cd and S were studied by X-ray photoelectron spectra. The topography and roughness of the films were explored by atomic force microscopy. The films exhibited high transmittance in visible region with 2.5 eV bandgap. All the samples showed photocurrent response under irradiation for white light as well as selected wavelengths of visible light emitting diodes from which the electrical properties were evaluated. The results showed that the laser irradiation by various wavelengths was effective in modification of surface topography and optoelectronic properties of the polycrystalline CdS thin films.