Vapor-solid growth ZnO:ZrO2 micro and nanocomposites

Abstract

Microstructures of ZnO and ZrO2 and the corresponding composites have been grown by the Vapor-Solid method. A detailed characterization of their structural, compositional and optical properties has been performed. X-ray diffraction (XRD) and Raman spectroscopy measurements, let us identify two main phases, wurtzite ZnO and monoclinic ZrO2, reinforcing the hypothesis of ZnO/ZrO2 composite formation. Scanning Electron Microscopy observations reveal the presence of different morphologies depending on the synthesis conditions. Chemical composition was analyzed by energy dispersive X-ray (EDX) spectroscopy. Luminescence properties were studied by photoluminescence and cathodoluminescence. Our results indicate that doping is occurring in both phases: ZnO is doped with Zr and ZrO2 is doped with Zn. However important differences between Zr rich and Zn rich structures are encountered. While the Zn rich structures are single phase with the characteristic wurtzite crystal structure of ZnO, the Zr rich structures are multiphase with both monoclinic and wurtzite crystal structures present, then leading to formation of the composites with interesting luminescence properties, with intense emissions in the near UV and the visble range, even at room temperature.