Preparation and Characterization of N-CdS Thin Films and its Schottky Barrier

Abstract

Cadmium sulphide (CdS), a member of group II-VI semiconductors is one of the promising materials from its applications point of view. The present investigations are about the preparation, structural and optical characterization of CdS thin films and their use as Schottky diode with Aluminum. Thin films of CdS having thickness around 700nm have been deposited by thermal evaporation. The chemical composition of the deposited CdS thin films has been made using EDAX technique. The structural characterization of this films was carried out using XRD. The structure of CdS after the deposition was found to be Cubic. Also, the lattice parameters were evaluated from the XRD data. From TEM of CdS thin films, the polycrystalline nature was confirmed. Optical characterization has been carried out using UV-VIS-IR spectroscopy. The direct as well as indirect band gaps obtained are 1.64eV and 1.48eV respectively. Schottky junctions were formed by a thermal vapor-deposition of 500nm Al films on pre-coated CdS glass substrates. Diode parameters, such as the zero bias barrier height φb0, the flat band barrier height φbf and the ideality factorη, were calculated using thermionic emission theory at room temperature.