Structural and opto-electrical study of as-grown CuS thin film doped with Sn by facile chemical bath deposition for solar cell application

Herein we report, tin (Sn) doped copper sulphide(CTS) thin films deposited on commercial glass substrates at room temperature throughin-situ chemical bath deposition. For the synthesis of CuS (CS) thin film aqueous solution of cupric chloride with thiourea was prepared. Triethanolamine was used as complexing agent. PH of the precursor solution has been adjusted using ammonium hydroxide solution. Doping was accomplished by Sn in to the chemical bath using hydrated stannic chloride solution. The structural, morphological properties of the thin films are investigated in detail. The XRD analysis revealed that both the doped and undoped films are polycrystalline in nature and was indexed to be of covellite CuS phase. Morphological characteristics showedrod shaped nanoparticles of size in range 150 nm- 250 nm for CuS film and spherical nanoparticles for the Sn doped CuS thin films whose size ranges in the same order as that of the CuS thin films. AFM revealed the rough surface topographyof the CuS film. UV-vis spectroscopy shows that optical energy band gap ofCuS thin film increases with Sn incorporation. The electrical conductivity of the pure CuS thin film is enhanced with Sn doping. The carrier concentrations determined from the Hall measurements came out to be 1017 cm−3, stating both the undoped and Sn doped CuS thin films were semiconducting in nature.