Effect of Cu-doping on the microstructural and optical properties of Mg_0.2Zn_0.8O thin films prepared by sol-gel spin coating

Cu-doped Mg_0.2Zn_0.8O thin films were synthesized by sol-gelspin coating. We investigated the microstructural and optical characteristics of the Cu-doped Mg_0.2Zn_0.8O thin films. By increasing the Cu content of the source, Cu-doped Mg_0.2Zn _0.8O thin films were phase-separatedinto Cu-rich and Cu-poor areas, which could be a result of the limited Cu solubility in the Mg _0.2Zn_0.8O lattice. As the annealing temperature increased, the crystallinity of the Cu-doped Mg_0.2Zn_0.8O thin films improved. Cu doping in Mg_0.2Zn_0.8O thin films resulted in a decrease of both intensities for UV and visible emissions without a shift of the peak positionsin the photoluminescence spectrum.