Synthesis And Characterization Of Metal Oxide Nanowires And Composite Metal Oxide Nanowires By Electrophoretic Deposition Method Based On Anodic Aluminum Oxide Membranes

One dimensional (1-D) Nano-materials (nanotubes, nanowires, nanorods) are basic units of nanodevices. They have great applied potential in optical information storage, single-electron transport devices, luminescence display and electronic sensors. A great number of synthesis methods have been exploited, through which 1-D nano-materials of various materials have been synthesized. However , most of the obtained 1-D nano-materials are single material,while composite materials are hardly ever concerned.In fact, the study of nano-composites, especially, nano-composites of metal oxides have been hot pursued. Because the compositeness of materials makes heterogeneous structures, nano-composites have fantastic properties in optics, photo-catalysis and sensors. Tin oxide, zinc oxide and titanium oxide are all important inorganic semiconductors with broad applied potentials. Their composites have great applied value in photo-catalysis, environment preservation, gas sensor, solar-cell, and electrode material of Li-ion cell. However the past studies on their composite were mainly about nanoparticles (0-D) and nanofilms (2-D), while the studies on nanowires and nanotubes (1-D) developed slowly for lack of proper synthesis route.The fabrication method through porous anodic aluminum oxide (AAO) membranes is an effective and cheap way for synthesizing large area 1-D nano-structure arrays. The products by this way have uniform morphology and are prone to form arrays and devices. AAO template method often works with other methods together, of which electrophoretic deposition method is a new and effective way. By electrophoretic deposition method, sol particles with certain charge were driven to certain electrode by the force of external electro-field and aggregated into the AAO template nano-holes to form high-rate filled nanowire arrays. According to the principle of electrophoretic deposition, the way combined with AAO template method and electrophoretic deposition method can be used in fabricating composite nanowire arrays.The major work in this dissertation includes the following three parts:1. Synthesis and characterization of AAO template.The porous AAO was fabricated on the surface of the electro-polished aluminum foils by a two–step anodic oxidation method, using vitriol acid,oxalic acid and phosphate acid as electrolyte. We can obtain AAO templates with different pore size which were characterized by SEM and AFM. The best experimental conditions of two–step anodic oxidation method were summarized.2. Synthesis and characterization of single SnO₂,ZnO nanowire arrays.SnO₂,ZnO nanowire arrays were fabricated in AAO templates by electrophoretic deposition method combined with AAO template method. This work proved the feasibility of synthesizing metal oxide nanaowires by electrophoretic deposition method combined with AAO template method. In addition, the equipment for electrophoretic deposition was set up and experimental conditions were studied. It made good preparation for the next step--- electrophoretic deposition for composite nanowire arrays. In the end, the microstructure of SnO₂,ZnO nanowire arrays was discussed.3. Synthesis and characterization of composite nanowire arrays.TiO₂/ZnO composite nanowire arrays have been successfully synthesized by a creationary electrophoretic deposition method combined with AAO template method. The results indicate that this method is practical for fabricating composite nanowires. The mechanism of electrophoretic deposition was discussed and summarized, as well as the best deposition conditions and concerned matters in the course of electrophoretic deposition.