Controllable Preparation And Electron Transportation Of One-dimension Metal Silver Nanowires

One dimension nanomaterials have received considerable attention over the past decades because of their novel physical and chemical properties and potential applications in future nanodevices. It is still a great challenge to prepare nanomaterials with controllable morphology, crystal structure and performance, to utilize the controllable nanostructures in nanodevices. Anodic alumina oxide (AAO) template is a useful implement to prepare one dimension nano-arrays because of uniform diameter, shape controllable and economic frugality. Considering the latest research progresses at home and abroad, we have mainly done some jobs on the investigation of morphology, crystal structure and electron transportation as described in this dissertation.Firstly, we prepared AAO templates with different morphology through two-step anode oxidation and then electric-deposited silver nanowires (Ag NWs) with the same morphology as the nanoholes using two-electrode method. FE-SEM and XRD were used to character the morphology and crystal structure of Ag NWs. The results indicated that the nanowires copied the shape of nanoholes perfectly. Ag NW as prepared by changing oxidation voltage linearly and then rapidly owns gradient bole and straight branch; the one as prepared by changing oxidation voltage linearly and periodically owns periodic gradient morphology.Further more, Ag NWs with metastable 4H crystal structure inside AAO membranes were prepared using alternating current (ac) electrodepositing method. Influence of deposition voltage, pH, and annealing temperature on formation of 4H structure of Ag NWs were investigated. It was found that there coexists 4H and fcc structure in the deposited Ag NWs, and the 4H-Ag has a favorable growth at relatively low deposition voltage and pH value. The annealing above 400℃results in the transformation of 4H-Ag into fcc-Ag. Furthermore, an alternant electrodepositing mechanism was tentatively proposed to explain the coexistence of 4H- and fcc-Ag in the deposited Ag NWs.In addition, electron transportation of Ag NWs in AAO was studied, and the results showed that electron transportation ability of Ag NWs decreased with the minishing of diameter; Ag NWs as electrodeposited in the AAO nanoholes had an apparent ferroelectric phenomenon at relatively low temperature. The collective behavior of Ag NWs and AAO template maybe responsible for this result, and the gospel need further research to be found.