Influence of cadmium precursor concentrations on the structural, optical and electrochemical impedance properties of CdZnS thin films

• Published in: Vacuum Vol. 160; pp. 246 - 254
• Main Authors: Offiah, Solomon U., Agbogu, Ada N.C., Nwanya, Assumpta C., Nkele, Agnes C., Chime, Ugochi K., Sone, B.T., Duvenhage, M.M., Botha, S., Ekwealor, A.B.C., Osuji, R.U., Maaza, M., Ezema, Fabian I.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2019
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2018.11.041

Thin films of cadmium zinc sulfide (CdZnS) were deposited on microscopic glass substrates using the chemical bath deposition method and the effects of the Cd precursor concentrations on the morphological, structural and optical properties of the films were studied. The surface morphology as revealed by scanning electron microscope showed closely packed nano particles randomly spread on the surface of the glass substrates. The x-ray diffraction studies showed that the thin films were polycrystalline and the crystallite sizedecreased with increase in the concentration of the Cd precursor. While the optical absorbance decreased, the bandgap energy increased as the concentration of the cadmium source increased. Electrochemical studies were performed by cyclic voltammetry analysis and impedance measurements at low frequency ranges. Simulation model on the impedance model was carried out to obtain a more quantitative analysis of the data. The ternary CdZnS thin film developed in this work could be useful as window layer in solar cell fabrication.
•A rotating machine at approximately 34 rev/min was used in CBD to deposited CdZnS thin film.•CdZnS thin films consist of closely packed and randomly spread nano-particles.•Bandgap energies of the films range from 3.26 eV to 3.75 eV.•The EIS shows strong combination of passive circuit elements to give a resultant current based on Ohm’s law.