Fabrication and Characterization of Nanostructured NiO and NiO:Cu Thin Films at Varied Copper Concentrations

Nickel oxide (NiO) is a semiconductor with a face-centered cubic (fcc) crystalline structure. Due to its wide band gap, high transparency, and porous surface morphology, NiO exhibits high performance in various electronic and optoelectronic devices. For this reason, metal-doped NiO thin films have recently attracted the attention of researchers. In this study, NiO and copper-doped (Cu-doped) NiO thin films were deposited on glass substrates at a temperature of 420 °C using a simple and cost-effective spray pyrolysis technique. The amount of Cu doping was varied at different concentrations (0.5 %, 1.5 %, 3 %, and 6 % by weight). The structure, morphology, chemical composition, optical properties and 3D topography analysis of the deposited films were investigated. X-ray diffraction analysis shows that both NiO and Cu-doped NiO films exhibit an fcc structure with a dominant (111) peak. The crystallite size decreases from 26.78 to 18.15 nm with Cu doping. Surface morphology was examined using a scanning electron microscope (SEM). In the SEM images, all samples show the formation of small aggregates of irregular particles on the heterogeneous surface. The chemical composition and stoichiometry of the deposited thin films were confirmed by energy-dispersive X-ray spectroscopy (EDS). The optical band gap (Eg) of the deposited films was determined through absorption measurements, demonstrating a decrease with increasing concentrations of Cu dopant.