Porous alumina thin films on conductive substrates for templated 1-dimensional nanostructuring

The growth of thin porous anodic aluminum oxide (AAO) films on silicon by anodizing Al on Ti/Au/Si and Ti/Pt/Si substrates in oxalic acid was demonstrated. Removal of the Al2O3 barrier layer was effected by selective chemical etching in H3PO4 and a reversed bias method in the anodizing solution. Ion transport and the influence of the Ti adhesion layer at the oxide-metal interface during the critical stages of anodization and pore opening were investigated. The AAO films may be exploited as templates in the creation of silicon-integrated nanostructured wire arrays. Electrodeposition of Pt into the AAO template yielded a nanowire array with superior methanol oxidation activity that can be integrated in a micro direct methanol fuel cell. (C) 2012 Elsevier B.V. All rights reserved.