Fabrication, Characterization And Properties Of One-dimension Nanowire Arrays Based On AAO Membrane

One-dimensional nanoscale materials, such as nanotubes, nanowires and nanobelts, have attracted considerable attention due to not only their novel physical and chemical properties compared with those of their bulk counterparts, but also their potential applications in the fields of electronics, magnetic recording, optoelectronic devices and so on. Therefore, they become the frontier and focus of nano-materials. Anodic aluminum oxide (AAO) membrane prepared by anodizing of Al not only has a simple process, but also contains uniform parallel pores and high pore density. Furthermore the pore diameter is controllable according to practical needs. These characteristics allow the use of AAO as membrane. As a traditional technique, electrodeposition has some advantages: simple technique, easy control of the deposited quantity of metal ions, suitable for large-scale production, less pollution to the environment and without complicate post-treatment. Many kinds of the nanowire arrays, for example, metals, alloys, oxides and sulfides, have been fabricated using electro-codeposition into the pores of the AAO membrane.The main contents and conclusions as following:1. Highly uniform porous AAO membranes with different pore diameters were successfully fabricated in 0.3 M H₂C₂O₄ electrolyte and 1.2 M H₂SO₄ electrolyte using two-step anodic oxidation, the field emission scanning electron microscope (FE-SEM, JSM-6700F) characterized the morphology of AAO membranes. The process laid a foundation for next electrodeposition.2. The compact Zn nanowire array was synthesized in the pores of AAO membrane by dc electrodeposition at room temperature, and then obtained high density polycrystal ZnO nanowire array with different temperature and time. The structure of the sample was characterized by FE-SEM and X-ray diffraction (XRD); the UV-Vis (ultraviolet-visible optical absorption measurement) result showed that the band gap of ZnO nanowire was consistent with block ZnO.3. The Zn-Fe alloy nanowire array was fabricated in AAO membrane using electro-codeposition, and then the sample was annealed in tubular furnace at 450℃for 35 hours. Finally, the Fe-doped ZnO nanowire array obtained after the sample cooled to room temperature. The morphology, chemical composition and crystal structure of the as-synthesized Fe-doped ZnO nanowire array were examined by FE-SEM, XRD and high resolution transmission electron microscope (HRTEM, JEOL-2010) equipped with an energy dispersive x-ray spectrometer (EDS), these results proved that 22% atomic ratio Fe was doped into the obtained ZnO nanowires . The magnetic property was investigated by micro-superconducting quantum interference device (SQUID, MPMS XL-7) magnetometry, the results showed that the nanowire arrays exhibit room temperature (300K) ferromagnetic and anisotropic ferromagnetic behavior.4. The Zn-Co, Zn-Ni alloy nanowire array were synthesized in AAO by electro-codeposition. The Co-doped ZnO nanowire array was successfully synthesized after the Zn-Co nanowire array was annealed in box type resistor furnace at 350℃for 48 hours, the UV-Vis result showed the band gap of ZnO increased; the ideal Ni-doped ZnO nanowire array was not obtained because the Zn-Ni alloy was hardly oxidized with its good corrosion resistance during anneal process.