The Structural and Optical Properties of Polycrystalline Copper Oxide Thin Films Synthesized Using the SILAR Technique

Abstract

In this study, polycrystalline copper oxide (CuO) thin films with the presence of various pH levels were fabricated using the successive ion layer adsorption and reaction (SILAR) method. The impact of pH on the structural and optical properties of the produced films was examined. The present films were characterized by X-ray diffraction (XRD) and UV-vis absorption spectroscopy measurements. The XRD result showed that all films had a polycrystalline nature with a monoclinic CuO crystal phase. Direct optical band gap energies of the films, determined using the Tauc equation, ranged from 1.49 eV to 2.89 eV. The optical parameters such as refractive index (n), extinction coefficient (k), real (ε_1), and imaginary (ε_2) parts of the dielectric constant were derived from the absorbance and transmittance spectra of the produced films. CuO thin film n values ranged from 3.10 to 11.14, while k values varied from 0.79 to 1.70. Likewise, the values of ε_1 and ε_2 for CuO thin films ranged from 8.96 to 121.15 and 4.89 to 37.90, respectively.