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.