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Abstract: Cu-doped Mg0.2Zn0.8O thin films were synthesized by sol–gel spin coating. We investigated the microstructural and optical characteristics of the Cu-doped Mg0.2Zn0.8O thin films. By increasing the Cu content of the source, Cu-doped Mg0.2Zn0.8O thin films were phase-separated into Cu-rich and Cu-poor areas, which could be a result of the limited Cu solubility in the Mg0.2Zn0.8O lattice. As the annealing temperature increased, the crystallinity of the Cu-doped Mg0.2Zn0.8O thin films improved. Cu doping in Mg0.2Zn0.8O thin films resulted in a decrease of both intensities for UV and visible emissions without a shift of the peak positions in the photoluminescence spectrum. [Copyright &y& Elsevier]

Abstract: The dependence of the MgO sputtering power on the structural and optical properties of epitaxially grown MgZnO thin films on GaN/sapphire substrates by radio-frequency magnetron sputtering was investigated. The photoluminescence investigation showed blue shift of 170 meV in MgZnO film grown at the MgO power of 300 W, compared with the ZnO films grown at the MgO power of 0 W, which was attributed to the enhancement of the Mg incorporation at higher power. In addition, increase in Mg mole fraction with increase in sputtering power of MgO was observed from the PL results, and a maximum of 6.6 at.% Mg was obtained at the MgO power of 300 W. The high-resolution X-ray diffraction and transmission electron microscopy (TEM) investigations revealed that the threading dislocation density in the MgZnO thin films increased with increase in sputtering power. Furthermore, microstructural analysis performed by TEM revealed formation of a thin cubic-like phase in the interface between GaN template and MgZnO thin film, together with increased thickness of the interfacial layer with sputtering power. [Copyright &y& Elsevier]

Abstract: This is a report on the effect of a ZnO buffer layer on the microstructures and optical properties of MgZnO thin films grown on Si (100) substrates by radio frequency magnetron sputtering. For the sample without the ZnO buffer layer, the microstructural analyses carried out by X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the formation of Mg2Si in the interface between the Si substrate and the MgZnO thin film. Mg2Si induced the random oriented polycrystalline MgZnO thin film. For the sample with the ZnO buffer layer, a few Mg2Si were observed. An epitaxial relationship between the Si substrate and the MgZnO thin film was formed. In both samples, the photoluminescence (PL) investigation showed a small blue shift of the emission peak, which was owing to the incorporation of Mg atoms in ZnO by co-sputtering the MgO and ZnO targets. In addition, the sample with the ZnO buffer layer showed the enhanced PL intensity, when compared with the sample without the buffer layer. [Copyright &y& Elsevier]