Electroplating of metal nanotubes and nanowires in a high aspect-ratio nanotemplate

Ordered metal (Co, Pt, and CoPt alloy) nanotube and nanowire structures were fabricated by a simple electroplating method in high aspect-ratio anodic aluminum oxide (AAO) membrane. The growth rate in pulse mode is always larger than that in constant-current mode, which represents that diffusion limitation exists in this electroplating condition. It is also found that the sputtered Au layer structure could influence the electroplating. Traditional nanowires could be fabricated in the template with a uniform Au layer as conducting contact. In case of unblocked AAO membrane, metal electroplating begins from the Au particles which were attached inside the holes during the sputtering step and produces metal nanotubes. Pt and CoPt nanotubes could be easily prepared by this method and might be applied as catalyst and magnetic material.