Preparation and Characterization of CdS Thin Films Prepared by Chemical Bath Deposition Route

Abstract

Cadmium sulphide is an extensive energy gap semiconductor, which has gained significance, since it is widely used in window layers in photovoltaic cells, gas sensors, antireflection coating, photo detectors, resistors, capacitors, transistors, and semiconductors for optoelectronic devices. CdS is an n-type compound with 2.4eV energy gap. Chemical Bath Deposition (CBD) method along with micro glass substrates is used in the preparation of CdS thin films at 80 • C with constant pH (10). X-ray diffraction patterns for CBD CdS thin films confirm that the peaks are finely coordinated with JCPDS data and exhibit cubic structure. The intensity of preferentially oriented direction of (200) plane increases with increase in deposition time period. Several structural aspects like grain size, strain and dislocation density of CdS films are determined depending on deposition time periods. Studies based on the optical properties of CdS thin films are conducted using absorbance spectra. The film directly transits at 2.48 eV. The deposition conditions can control the optical gap of the material. Due to such factors in the CdS films, they are opted for several optoelectronic and device applications.