Electrooptical Characterization Of CulnS Films Prepared By Chemical Bath Deposition Technique

Abstract

Solar energy because of its global abundant has the potential to be the world s foremost source of energy. Solar conversion energy with CuInS2 as an absorber layer is nearly about 13%. We have decided to synthesize CuInS2 (CIS) thin films by using very economical method called as chemical bath deposition method to reduce the costs and enhance the photo-electrochemical efficiency. The major concern of this work is to synthesize a film with high photoconductive gain so as to enhance the conversion efficiency of solar cells. The work is carried out to know the structural, electrical and optical properties of CIS thin films synthesized by using chemical bath deposition technique. In numerous studies, it was shown that the structural, optical and electrical properties of CIS thin films could be improved by optimizing deposition conditions and doping elements. In favor of controlling a conduction type and obtaining low resistivity, several impurities doped CuInS2 thin films have been studied. Thus rare earth elements are used as impurities to see its effect on the conductivity, photoconductive gain, mobility and band gaps of CuInS2 thin films. newlineFirstly the films have been synthesized at different temperature by using metal salts as precursors, which was optimized based on electrical and optical characterization. The synthesized film on microscopic glass slides at 800C shows good optical characteristics and high photoconductive gain. This was named as undoped film. Then rare earth elements samarium (Sm), holmium (Ho) and praseodymium (Pr) were added in presence of flux CdCl2 with varying volume as doping element to the precursors to see its effect on the electrical and optical properties of as synthesized CIS films at 800C. These films were named as doped films. newlineThe crystallographic characterization was done by using X-ray diffraction (XRD) technique which shows polytypic structure which is a combination of both chalcopyrite and wurtzite phase in many of the synthesized films. Few films also shows chalcopyrite phase with