Properties of spray-deposited CdIn2Se4 thin films for photovoltaic applications

Abstract

Thin films of cadmium indium selenide have been deposited onto amorphous glass substrates using a simple and low-cost spray pyrolysis technique. The aqueous solutions containing precursors of Cd, In and Se have been used to obtain good quality deposits at optimized substrate temperature. The preparative parameters such as concentration, substrate temperature, etc. have been optimized by photoelectrochemical technique. The films have been characterized by techniques such as X-ray diffraction, scanning electron microscope, EDAX and electrical characterization. The photoelectrochemical characterization shows that both short-circuit current (I sc ) and open-circuit voltage (V oc ) are at their optimum values at the optimized substrate temperature of 280C and concentration (0.0125 M). The XRD patterns show that the films are polycrystalline with cubic structure. The SEM studies reveal the compact morphology with large number of grains. Compositional analysis reveals that the material formed is nearly stoichiometric at the optimized preparative parameters. The electrical resistivity shows that the films are semiconducting and the resistivity is found to be minimum at optimized substrate temperature. The thermoelectric power (TEP) measurement reveals that the TEP is relatively maximum at same substrate temperature of 80°C. Photovoltaic output characteristics study reveals that the fill factor and efficiency; to be 69% and 3%, respectively.