| Nanostructure materials are attracting more and more attentions for its unique physical and chemical characteristics, and the one-dimensional nanowires (NWs) have a variety of potential applications based on their unique properties. Recently, preparing and investigating its unique characteristics is drawing more and more attentions. In this letter, single SnO2 or ZnO nanowire (NW) synthesized by chemical vapor deposition (CVD) was aligned onto paired Pt electrodes using AC electric field assembly, and its optoelectric and transport properties were studied.In Chapter 2, the ZnO NWs were synthesized by CVD and characterized by SEM, TEM, XRD, HRTEM and SAED. Then the as-synthesized ZnO samples were placed in ethanol and ultrasonicated to disperse the bundles into individual NWs. A single ZnO NW was aligned by AC electric field assembly.In Chapter 3, a single ZnO NW was assembled on a pair of Pt electrodes by dielectrophoresis, and a back-to-back Schottky barriers (SBs) structure was formed. The photocurrent of the ZnO NW Schottky photodiode (SPD) was unsaturated, and its differential conductivity increased with the increasing of reverse bias, which was opposite to the saturated property for two-dimensional (2-D) planar SPD. It was found that this unsaturated photocurrent property was controlled by the 2-D SB geometry of NW, in which the barrier width was smaller than the diameter of NW and the photogenerated electron-hole pairs were separated along the radial direction of NW. The photocurrent equation for this 2-D SB geometry model was obtain, which was in good agreement with the experimental results. In Chapter 4, the SnO2 NWs synthesized by CVD method were ultrasonically dispersed in ethanol and then: (1) a single NW is"placed"across the prefabricated electrodes using the AC field assembly; (2) the NWs were dropped on the ITO substrate. The I-V characteristics were studied by Scanning Probe Micrscope.
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