Structural, electrical and optical characterization of CuInS₂ thin films deposited by spray pyrolysis

Abstract

Copper indium disulphide (CuInS₂) thin films have been deposited on glass substrates by varying Cu:In and S:Cu ratios using spray pyrolysis deposition. The structural, compositional and electrical characterizations of the thin films have been analyzed by Energy Dispersive X-ray Analysis (EDAX), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), <i>dc</i> conductivity measurement and UV-VIS-NIR Spectrophotometry. The surface morphology has beenn studied by SEM. From XRD spectrum, the fundamental peaks of CuInS₂ (CIS) thin films have been identified as (112), (004)/(200), (204)/(220), (116)/(312) and (224) which indicate the chalcopyrite structure and showed an improvement of crystallinity of CuInS₂ thin films for Cu:In:S ratio of 1.14:1:1.88. The temperature variation of <i>dc</i> conductivity showed its semiconducting nature in all the films and the highest conductivity was estimated as 11.1786 (<img src='http://www.niscair.res.in/jinfo/omega1.gif' border=0>-cm)^-1 and the corresponding band gap of 1.48eV.