Investigation of the structural, optical and electronic properties of different alkaline metal additive CdS thin films produced by the chemical bath method

In this study, CdS thin films used as a buffer layer in thin-film solar cells were coated on FTO substrates by chemical bath deposition method. Alkali metal doped CdS thin films were produced by adding NaCl, KCl, RbCl and CsCl salts into the chemical bath solution. Structural, electrical and optical properties of the alkali metal doped CdS thin films were investigated by using FE-SEM, XRD, HEMS and Uv-Vis measurements with respect to the type and amount of doped alkali metal. Na, K, Rb and Cs alkali metals were each added into the chemical bath at concentrations of 20 mM, 30 mM, 40 mM and 50 mM, respectively. So, the CdS thin films were doped with the corresponding alkali metals. The variation of the effectiveness of these dopings according to the alkali metal type and concentration was investigated. It was observed that doping with 30 mM and 40 mM concentrations affected the properties of the CdS thin film more positively compared to other concentrations, especially regardless of the alkali type, and the characteristic properties of the obtained film were improved structural and electrical.