Preparation and Characterization of Hot Wall Deposited CuInGaSe<sub>2</sub> Thin Films for Solar Cell Applications

Abstract

CuIn0.7Ga0.3Se2 (CIGS) bulk compound was prepared by direct reaction of high purity (99.99%) elemental copper, indium, gallium and selenium. Using the prepared bulk CIGS, polycrystalline CuInGaSe2 thin films were deposited onto well cleaned soda-lime glass substrates using hot wall deposition technique by optimizing process parameters such as the wall temperature, filament current and time of deposition. The x-ray diffraction studies on the as-prepared films revealed polycrystalline nature. The composition of the chemical constituents present in the prepared bulk and thin films has been determined using energy dispersive X-ray analysis (EDX). The surface morphology of CIGS thin film of deposition time 3 min. have been carried out using Atomic Force Microscopy (AFM). The AFM images revealed that the average grain size was 20 nm and the surface roughness was about 8 nm. Transmittance spectra in the wavelength range of 190 nm to 2500 nm was obtained using a double beam spectrophotometer (UV-VIS) and the results are discussed.