Chemical bath deposition and characterization of Cu_2O-Cu_xS thin films

Authors: D. D. O. EYA

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 2.19-2.32 eV and with film thickness 0.54 \mu m-1.30 \mu m. The extinction coefficient and refractive index are in the ranges of 5.41 \times 10^{-2} - 20.11 \times 10^{-2} and 1.60-2.60, 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.

Keywords: Chemical bath, optical properties, transmittance, energy band gap, solar control, Copper (I) Sulphide, annealing

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