Fabrication of ZnO-TiO2 axial micro-heterostructures by a vapor-solid method

Elongated micro-heterostructures formed by ZnO and TiO2 have been fabricated using a single step thermal treatment at 900 °C. ZnO, Ti and TiN powders have been used as precursors during the synthesis. The as-grown micro-heterostructures have been characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and cathodoluminescence (CL). Compositional analysis indicates that the ZnO microrods grow from a rutile-TiO2 base. The presence of a ternary compound Zn2TiO4 has been detected at the region between the Zn doped TiO2 base and the Ti doped ZnO microrod, as confirmed by XRD and EDS results. Luminescence of the heterostructures is formed by two main emissions at 3.2 and 1.5 eV, which correspond to the ZnO and the TiO2 regions, respectively.