Chemical bath deposition and characterization of $Cu _2O - Cu _xS $ thin films

Abstract

$Cu _2O - Cu _xS $ thin films have been deposited on glass substrate by chemical bath deposition technique. The films were obtained by depositing Copper Sulphide ($Cu _xS $) on Copper (I) Oxide ($Cu _2O $) and then $Cu _2O on Cu _xS $. The peak solar transmittance across the thin films were found to be < 40% and as low as 10%, and falls with energy into the infra-red region. The absorbance is higher near the UV and IR regions. Reflectance is < 20%. The band gap of both respective combinations is in the range of 2.19&#8211;2.32 eV and with film thickness 0.54 &#956;m&#8211;1.30 &#956;m. The extinction coefficient and refractive index are in the ranges of 5.41×$10^ {-2} $ &#8211; 20.11×$10^ {-2} $ and 1.60&#8211;2.60, respectively. Since the absorbance increases as one goes towards the IR region, the films could be useful in solar control (providing cool interior) in tropical regions.