Impact of deposition voltage on the physicochemical properties of electrodeposited Se-doped CdTe thin films for solar cell applications

Abstract In this study, using cadmium acetate, selenium dioxide, and tellurium dioxide as Cd, Se, and Te precursors, respectively, CdTe:Se was electrochemically deposited in a simple two-electrode deposition setup. Unlike most previous studies, this work focuses specifically on the influence of deposition voltage on the properties of Se-doped CdTe, an area that remains largely unexplored. At deposition voltages of 1860, 1870, 1880, 1890, and 1900 mV, the thin films were produced. To assess the characteristics of CdTe:Se thin films, X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and scanning probe microscopy (SPM) were employed. XRD analysis confirmed that the CdTe:Se thin films are polycrystalline with a cubic crystal structure, exhibiting a strong (111) preferred orientation along with additional peaks corresponding to (220) and (311) planes. At a growth voltage of 1890 mV, the following parameters were measured: lowest micro strain, dislocation density, and maximum crystallite size. As the deposition voltage rose from 1860 to 1900 mV, the energy bandgap of CdTe:Se thin films changed and decreased from 1.82 to 1.62 eV, according to the UV-Vis study. The maximum average surface roughness observed, using a cathodic voltage of 1890 mV, was 59.37 nm. Therefore, a deposition voltage of 1890 mV may be best to produce CdTe:Se thin film, which might be used in thin-film solar cell systems.