Physico-chemical studies of Cd1−xZnxS thin films produced by simple two-electrode electrodeposition system for solar cell application

• Published in: Journal of materials science. Materials in electronics 2019-03, Vol.30 (6), p.6201-6211
• Main Authors: Werta, S. Z., Echendu, O. K., Dejene, F. B.
• Format: Article
• Language: English
• Subjects: Cadmium; Cadmium sulfide; Cadmium tellurides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Electrodes; Electrolytic cells; Energy dispersive X ray spectroscopy; Energy gap; Film thickness; Fluorine; Glass substrates; Materials Science; Morphology; Optical and Electronic Materials; Optical measurement; Optical properties; Organic chemistry; Photovoltaic cells; Raman spectroscopy; Scanning electron microscopy; Sodium thiosulfate; Solar cells; Spectrophotometry; Spectrum analysis; Thin films; Thiosulfates; Tin oxides; X-ray diffraction; Zinc chloride
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-019-00922-z

Cd 1−x Zn x S thin films have been cathodically electrodeposited on glass/fluorine-doped tin oxide substrates using a low-cost two-electrode configuration with an electrolytic bath containing cadmium chloride, zinc chloride and sodium thiosulphate precursors. The deposition was carried out by varying zinc chloride concentration (0 M, 0.3 M, 0.6 M and 0.9 M) in the deposition electrolyte. The structural, compositional, phonon vibrational, morphological and optical properties of the resulting films have been characterized using glancing incidence X-ray diffraction, energy-dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and UV–Vis spectrophotometry respectively. The XRD result indicates the existence of hexagonal structure of Cd 1−x Zn x S with intensities of the diffraction peaks decreasing as more Zn is incorporated into the film as a result of decrease in deposition rate. EDX results show the presence of Cd, Zn and S in the deposited Cd 1−x Zn x S thin films. SEM images show uniform and densely packed surface morphology of the films with distinct shaped grains which gradually less distinct as more Zn is incorporated into the films. The optical measurements reveal a significant increase in energy band gap of the Cd 1−x Zn x S material as more zinc is incorporated into the films and a film thickness decreases with the energy band gap increasing from 2.40 eV for CdS to 2.62 eV for Cd 1−x Zn x S. These results show that Cd 1−x Zn x S material can be applied as a better window material for CdTe, CIG(S,Se) and CZTS-based solar cells than CdS.