Controlled pore diameter in porous anodic aluminium oxide templates for nanotube/nanowire fabrication

A porous anodic aluminium oxide (AAO) templates were fabricated on aluminium by electrodeposition method using a two-step anodization process. The AAO templates were anodized in 0.3 M oxalic acid solution by applying a constant voltage of 40V, which was afterward treated with chemical etching process in a mixed solution of 6% phosphoric acid and 1.8% chromic acid, respectively. The temperature was kept constant in 15oC during the anodization process and the anodization time were done between 20 to 60 min. All the samples were characterized using by scanning electron microscopy (SEM) to study the surface morphology of AAO templates. It was found that the pore diameters of AAO templates can be controlled by changing the anodizing time. The influence of the electropolishing were also discussed. Highly uniform self-ordered AAO template were effectively formed from these polished foils via an anodizing process