A Controllable and Widely Applicable Electrochemical Anodization Process to Fabricate Porous Anodic Aluminum Oxide Membrane

Inspired by the versatile applications of porous alumina nanostructures on solar cells, supercapacitors, biosensors, and so forth, research on fabrication of anodized aluminum oxide (AAO) with nanopore structure has achieved substantial advancements. Porous AAO membrane with nanostructures has become one of the most popular template materials for synthesis of a broad range of functional nanostructures such as nanowires, nanopillars, nanotubes, etc. While fabrication of highly ordered nanoporous AAO with tunable geometric features has been widely reported, its growth rate can be easily affected by the fluctuation of parameters such as acid concentration and temperature during the electrochemical anodization process. In order to meet the demand of fabricating AAO with various surface parameters and precise target pore depth control for scientific research and commercial applications, a controllable fabrication process is essential. Here, we developed a method which can implement precise pore depth control of AAO layer during the electrochemical anodization process, via monitoring the integrated charge. This method is applicable in a large voltage range and can be widely applied in fabrication of nanostructure with material such as TiO₂and so on.