Selective barrier perforation in porous alumina anodized on substrates

Abstract

A new method for perforating the barrier oxide at the base of pores in alumina, which does not involve etching of the alumina, is reported. Anodization of Al layers on W leads to formation of WO3 "Plugs" that can be selectively etched without widening the as-anodized pores. We demonstrate this technique, used with templated pore formation, by creating Ni nanoelectrode arrays with fixed electrode spacings (200 nm) but varied electrode diameters.