SILAR growth of pure CdO and copper-doped CdO thin films: Structural, optical and electrical properties

This study explores the effects of copper (Cu) doping on the structural and optical properties of cadmium oxide (CdO) thin films, which are widely employed in optoelectronic applications. CdO thin films were synthesized using the Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates, followed by doping with CuO at varying concentrations. The resulting films were characterized using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDAX), and UV–Vis spectroscopy. XRD results revealed a cubic polycrystalline structure for both undoped and Cu-doped films. SEM analysis indicated a morphological shift from spherical to flower-like structures with increased Cu content, supported by elemental analysis via EDAX. Particle size distribution was calculated using SEM images. Optical studies showed a progressive decrease in the energy band gap from 2.48 eV (undoped CdO) to 1.99 eV (highest Cu doping level), highlighting the potential for tuning the electronic properties of CdO films through Cu doping. When the electrical properties of CdO and Cu-doped CdO thin films were examined, it was found that Cu doping decreased the resistivity. These findings demonstrate the effectiveness of Cu doping in enhancing the optoelectronic characteristics of CdO thin films for advanced device applications. © 2025 Elsevier B.V.