Templated surface sol-gel synthesis of SiO₂ nanotubes and SiO₂-insulated metal nanowires

The synthesis of silica nanotubes in anodic aluminum oxide membranes (AAO) using the surface sol-gel (SSG) technique was reported. To attempt to understand the dynamics of the tube growth, the process was monitored by transmission electron microscopy (TEM) and SiO₂ mass uptake measurement. While still in the membrane, the SiO₂-coated pore can be electro-chemically filled with metal and then released by etching in acid to give free-standing insulated wires. Such insulated wires were electrically characterized, and reported that the SSG method gives a very high-quality dielectric oxide.