Template-directed formation of functional complex metal-oxide nanostructures by combination of sol–gel processing and spin coating

We report the template-based formation of functional complex metal-oxide nanostructures by a combination of sol–gel processing and spin coating. This method employs the spin-coating of a sol–gel solution into an anodic aluminum oxide membrane (SSAM). Various metal-oxide nanowires and nanotubes with a high aspect-ratio were prepared. The aspect-ratios of the PbO2 nanowires and Pb(Zr0.52Ti0.48)O3 nanowires were about 300 and 400, respectively, and their diameters were about 50 nm. The fabricated PbTiO3 nanotubes have a relatively constant wall thickness of about 20 nm with an outer diameter of about 60 nm. The deposition time for all of the fabricated metal-oxide nanowires and nanotubes is less than 120 s, which is far shorter than those required in both the sol–gel dipping and sol–gel electrophoretic methods. These results indicate that the SSAM method can be a versatile pathway to prepare functional complex metal-oxide nanowires and nanotubes with a high aspect-ratio. The possible formation process for the one-dimensional nanostructures by SSAM is discussed.