Electrochemical deposition of CdTE and investigating the effect of potential deviation from stoichiometric potential

Subject Areas : journal of New Materials

Fateme Amirsardari Darjaz ¹ , Ali Mashreghi ²

1 - Materials Science and Engineering Department, Shiraz University of Technology, Shiraz, Iran
2 -

Received: 2025-03-09 Accepted : 2025-04-05 Published : 2025-04-15

Keywords: Electrochemical deposition, CdTe, Elemental atomic ratio, solar cell,

Abstract :

CdTe solar cells have a significant position in photovoltaic market due to their high efficiency and low cost. Among the various deposition techniques, electrochemical deposition offers simple and inexpensive method for CdTe fabrication. At a specific voltage, stoichiometric CdTe films can be obtained. Since the reduction potential of tellurium ions is more positive than that of cadmium ions, anodic deviation from the stoichiometric voltage leads to tellurium-rich CdTe films, while cathodic deviation results in cadmium-rich CdTe films. In this study, CdTe thin films were electrochemically deposited at the stoichiometric voltage of 1600 mV, as well as at slightly anodic (1580 mV) and cathodic (1620 mV) voltages. Elemental analysis using energy dispersive spectroscopy (EDS) method revealed that the Cd/Te atomic ratios at 1580, 1600, and 1620 mV were 0.97, 1.00, and 1.03, respectively This finding indicates the formation of tellurium-rich, stoichiometric and cadmium-rich CdTe layers. X-ray diffraction (XRD) analysis confirmed that all deposited layers were single phase CdTe without any secondary phases. The real thickness of the obtained films, measured via scanning electron microscopy (SEM) cross-sectional images, was compared with the theoretical thickness calculated from current-time curves. The obtained results revealed a decrease in deposition efficiency with cathodic deviation. Top-view SEM images showed that all CdTe layers consisted of micrometer sized dendritic structures. The obtained results demonstrate that by controlling deposition voltage, CdTe films with tailored stoichiometry can be produced, enabling precise control over their electrical properties for photovoltaic applications.

References:

1. Pastuszak, J. and P. Węgierek, Photovoltaic cell generations and current research directions for their development. Materials, 2022. 15(16): p. 5542.
2. Scarpulla, M.A., et al., CdTe-based thin film photovoltaics: Recent advances, current challenges and future prospects. Solar Energy Materials and Solar Cells, 2023. 255: p. 112289.
3. Kujovic, L., et al., Achieving 21.4% efficient CdSeTe/CdTe solar cells using highly resistive intrinsic ZnO buffer layers. Advanced Functional Materials, 2024. 34(14): p. 2312528.
4. Metzger, W.K., et al., As-doped CdSeTe solar cells achieving 22% efficiency with− 0.23%/° C temperature coefficient. IEEE Journal of Photovoltaics, 2022. 12(6): p. 1435-1438.
5. Kumarasinghe, P., et al., Thermally evaporated CdTe thin films for solar cell applications: optimization of physical properties. Materials Research Bulletin, 2017. 96: p. 188-195.
6. Doroody, C., et al., Temperature difference in close-spaced sublimation (CSS) growth of CdTe thin film on ultra-thin glass substrate. Results in Physics, 2020. 18: p. 103213.
7. Kestner, J.M., et al., An experimental and modeling analysis of vapor transport deposition of cadmium telluride. Solar energy materials and solar cells, 2004. 83(1): p. 55-65.
8. Ling, J., et al., Electrodeposition of CdTe thin films for solar energy water splitting. Materials, 2020. 13(7): p. 1536.
9. Lepiller, C. and D. Lincot, New facets of CdTe electrodeposition in acidic solutions with higher tellurium concentrations. Journal of the Electrochemical Society, 2004. 151(5): p. C348.
10. Sella, C., P. Boncorps, and J. Vedel, The electrodeposition mechanism of CdTe from acidic aqueous solutions. Journal of the Electrochemical Society, 1986. 133(10): p. 2043.
11. Yimamu, A., et al., The effect of electrolytic solution pH on the properties of electrodeposited CdTe thin films for solar energy application. Optical Materials, 2024. 151: p. 115340.
12. Panicker, M., M. Knaster, and F. Kroger, Cathodic deposition of CdTe from aqueous electrolytes. Journal of the Electrochemical Society, 1978. 125(4): p. 566.
13. Echendu, O., et al., Electrochemical Deposition of CdTe Semiconductor Thin Films for Solar Cell Application Using Two‐Electrode and Three‐Electrode Configurations: A Comparative Study. Advances in Materials Science and Engineering, 2016. 2016(1): p. 3581725.
14. Mashreghi, A., K. Maleki, and M. Moradzadeh, Two-phase synthesized Cu2ZnSnS4 nanoparticles as inorganic hole-transporting material of paintable carbon-based perovskite solar cells. Solar Energy, 2020. 201: p. 547-554.
15. Ojo, A. and I. Dharmadasa, Analysis of electrodeposited CdTe thin films grown using cadmium chloride precursor for applications in solar cells. Journal of Materials Science: Materials in Electronics, 2017. 28: p. 14110-14120.