Influence of deposition temperature on properties of electrochemically grown Mg-doped CdS thin films for solar cell application

Magnesium-doped cadmium sulfide (CdS:Mg) thin films were successfully deposited on glass/indium-doped tin oxide (glass/ITO) using the electrodeposition technique. The concentration of cadmium chloride (CdCl₂), magnesium chloride (MgCl₂), and sodium thiosulfate (Na₂S₂O₃) in the electrolytic solution was 0.3, 0.06, and 0.03 M, respectively. Temperatures of 70, 75, 80, and 85 °C were used for the deposition process. Using a two-electrode setup, the matching characteristics in terms of structural, optical, morphological, photoluminescence, and compositional properties of these thin films were investigated by means of energy dispersive X-ray spectroscopy, room-temperature photoluminescence (PL), scanning electron spectroscopy, UV–Vis spectrophotometry, and X-ray diffraction, respectively. The results show that a film’s structural, optical, and morphological properties are strongly influenced by the temperature at which it is deposited. As the temperature of the electrolytic solution increased, the CdS:Mg thin film’s crystallinity improved. The bath temperature rises from 70 to 85 °C, resulting in a drop in energy bandgap film from 2.74 to 2.39 eV, and the surface roughness falls from 9.5 to 2.75 nm for the deposited Magnesium-doped Cadmium sulfide (CdS:Mg) thin films. The S-to-Cd atomic ratio is improved by raising the deposition temperature as both S and Cd elemental composition were proportionally increased with temperature. In a same vein, as the temperature rises, so do the film’s grains.