Fabrication And Characterization Of ZnO Nanostructures

Fabrication and properties of nanomaterials are attracting considerable attention recently. Among these materials, functional oxide semiconductor nanomaterials are especially popular, because not only various nanostructures have been synthesized, but also the nanodevices based on these nanostructures can be widely used in optics, electronics, magnetism, gas sensing and field emitting. ZnO nanomaterials are especially popular because of excellent properties. It is attracting considerable attention that improving ZnO properties by doping. This paper is mainly focused on ZnO nanostructures:1. Synthesis Co-doped ZnO nanowire array based on AAO membrane and optical propertiesAAO membranes are successfully fabricated using two-step anodic oxidation. The Zn-Co alloy nanowire array is fabricated in AAO membrane with electro-codeposition, and then the sample is annealed in furnace at 450℃for 48 hours. Finally, the Co-doped ZnO nanowire array obtained after the sample cool to room temperature. The UV-vis result shows the band gap of ZnO increased.2. Synthesis and photoluminescence of In-doped ZnO nanobelts.In-doped ZnO nanobelts have been synthesized by a thermal evaporation method with absence of any catalysts. The typical lengths of belts are in the range of several tens to several hundreds of micrometers, and the typical widths of the belts are several hundreds of nanometers. The belts are In-doped ZnO and ternary Zinc Indium Oxide by Energy Dispersive Spectrdmeter (EDS) and X-Ray Diffurction (XRD) results. The structure of the belts is hexagonal wurtzite. The belts grow along <1010> direction. It is different from generally preferred growth direction of pure ZnO because the doping of In influences the growth of ZnO. The growth mechanism of IZO belts is also discussed. The IZO belts follow a growth mechanism similar to the vapor–solid (VS) mechanism. Room temperature photoluminescence(PL) measurements under excitation at 325nm show that the IZO belts have a strong violet emission at around 425nm and a weak green emission at around 506nm. 3. Synthesis and optical properties of hollow ZnO-CdO nano-microspheresHollow ZnO-CdO nano-microspheres were successfully synthesized by a simple chemistry vapor deposition (CVD). The typical shape characteristic is that the spheres with larger diameter usually are hemispheric or broken spherical shell, while the appearance of the spheres with smaller diameter is perfect. The EDS and XRD results show that the samples are compound of ZnO-CdO. The morphology evolutions of the hollow spheres were discussed in detail. A possible model was proposed to demonstrate the formation of the hollow spheres. The photoluminescence property of the sample at room temperature was also investigated. The PL spectrum of the sample has a strong green peak centered at 505 nm (3.06 eV).