Structural, Optical and Chemical Surface Properties of Copper Oxide Thin Films

Thin films of copper oxide were prepared on glass substrates at 200 and 300^oC calcination temperatures, respectively. For this, copper acetate monohydrate was used as a precursor and glucose monohydrate as a reducing agent. The deposition technique was spin-coating, and the samples were structural, chemical, and optically characterized. Thus, X-ray Diffraction (XRD) measurements indicate the formation of CuO, while X-ray Emitted Photoelectron Spectroscopy (XPS) shows that the CuO phase is on the surface of the material, and the bulk is composed of Cu₂O for the sample annealed at 300^oC. While the sample annealed at 200^oC, the bulk shows the formation of Cu₂O structure coexisting with CuO phase. Furthermore, transmittance (T) spectra in the UV-visible region, from 190 to 1100 nm, were collected and fitted using the classical Lorentz scattering model of the complex dielectric function to obtain additional optical properties, such as the refraction index, and the extinction coefficient. In addition, first-principles calculations were performed using the Electronic Density Functional Theory (DFT) of Cu₂O and CuO systems to obtain the electronic band structure, density of state, and optical properties. These theoretical results were compared with those obtained experimentally and are discussed.