Cd_1−xZn_xS thin films with low Zn content obtained by an ammonia-free chemical bath deposition process

Cd_1−xZn_xS films with low Zn content were obtained on glass substrates by an ammonia-free chemical bath deposition process. Alkaline reaction solutions were prepared using cadmium chloride, zinc chloride, sodium citrate, thiourea and potassium hydroxide. As a result of varying the mixture ratio between Cd and Zn precursors, microstructural studies from X-ray diffraction reveal that the resulting films have hexagonal, wurzite type, crystalline structure with changes in the preferential growth orientation. Important changes on the surface morphology and thickness of the Cd_1−xZn_xS films were also observed as effects of adding Zn to the CdS lattice. Optical studies show that Cd_1−xZn_xS thin films with energy band gaps in the range from 2.48 to 2.65 eV were obtained. - Highlights: • Cd_1−xZn_xS layers were grown on glass by ammonia-free chemical bath deposition • Films with low Zn content were obtained using reaction solutions with pH11.5 • Zn addition produced changes on the orientation growth and morphology of the films • Cd_1−xZn_xS films have energy band gap values from 2.48 to 2.65 eV