Control of optical properties of ZnO nanostructures grown by a novel two-step synthesis approach

Wurtzite ZnO has been grown by electro-deposition of zinc on copper substrate followed by its hydrothermal oxidation in NaCl solution at 100–130 °C. Scanning electron microscopy has revealed the formation of nanowires and nanorods (with a diameter of about 100 nm to more 1 μm); and microtubes are numerously formed with a diameter of up to 3 μm. For microtubes of various diameters, the wall thickness remained about 0.9 μm. Optical studies illustrated strong ultraviolet emission in the photoluminescence and cathodoluminescence spectra without green luminescence, which suggests that high-quality ZnO structures are formed by our technique for ultraviolet photonic devices.