Processing and characterization of single-crystalline ultrafine bismuth nanowires

By pressure injecting Bi liquid melt into the nanochaanels of an anodic alu mina template, we have successfully fabricated Bi nanowire arrays with ultr afine wire diameters and extremely high wire packing densities. Free-standi ng Bi nanowires with controlled wire diameters and large aspect ratios (len gth/diameter) were also obtained by subsequent etching of the alumina templ ate. Various techniques such as SEM, TEM, AFM, EFM,HREM, and XRD have been used to investigate the physical characteristics of these nanowires. The Bi nanowires were found to be dense and continuous and had a uniform diameter throughout the length of the wires. Individual Bi nanowires were shown to be single crystals, and all the wires in an array were highly oriented. An interesting metastable phase of Bi was also observed, which can be attribut ed to a lattice stress-induced high-pressure phase of Bi formed inside the porous anodic alumina template.