Effect of surface morphology on optical properties of two multilayer structures CuO/ZnO/SiC and Al₂O₃/ZnO/SiC

Zinc oxide (ZnO) and Silicon carbide (SiC) thin films demonstrate unique properties such as high electron mobility, thermal stability, good chemical resistance, and low cost made them good candidates for optical applications. Moreover, semiconductors absorb short wavelengths of light due to the presence of a band gap. This work's purpose is to study the effect of deposited ZnO and SiC thin films by physical vapor deposition (PVD) above two different oxides and substrates. Copper (Cu) with copper oxide (CuO) and aluminum (Al) with aluminum oxide (Al₂O₃) were the used substrates and oxides. After deposition of thin films, two different multilayer structures were resulted, which are CuO/ZnO/SiC and Al₂O₃/ZnO/SiC. Microstructure and morphology were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Structure and phases identification were examined by X-ray diffraction (XRD). Optical properties (absorbance and emittance) before and after depositions of thin films were measured by spectrophotometer and Fourier transform infrared spectroscopy (FTIR). The results showed that the CuO/ZnO/SiC structure (85%) had higher absorbance than Al₂O₃/ZnO/SiC structure, however Al₂O₃/ZnO/SiC showed higher selectivity (absorbance/emittance (α/ε)) of about 0.65/0.15, compared to 0.85/0.5 for CuO/ZnO/SiC multilayer structure. The effect of surface topography and roughness on the efficiency of each multilayer structure has been studied.