Synthesis and Characterization of (Co3O4: CuO) Thin Films with Varying Mixture Ratios

Abstract
This study investigates the synthesis of Co₃O₄-CuO thin films with varying CuO ratios (20%, 40%, 60%, 80%) using the chemical spray pyrolysis technique. The impact of CuO content on the structural, morphological, optical, and electrical properties of the films is systematically analyzed. X-ray diffraction (XRD) analysis reveals a polycrystalline nature with a dominant (113) orientation, and crystallite size increases with higher CuO content. Field Emission Scanning Electron Microscopy (FE-SEM) shows that CuO incorporation leads to denser, more homogeneous films with larger grain sizes. UV-Vis spectroscopy indicates a decrease in the energy band gap with increasing CuO ratio, with the best absorbance observed in the 20% Co₃O₄: 80% CuO thin film. Photoluminescence spectra suggest excitonic emission peaks in the range of 500–900 nm, with varying peak positions as CuO content changes. Hall effect measurements confirm p-type conductivity for all films, with the 80% Co₃O₄: 20% CuO film exhibiting higher electrical conductivity than the 60% Co₃O₄: 40% CuO film. These findings highlight the significance of CuO incorporation in tuning the properties of Co₃O₄ thin films, making them promising for various optoelectronic applications.