Three-dimensional micro- and nanometre composite aluminium patterns

Three-dimensional micro- and nanometre composite aluminium patterns are constructed on Al substrate by using photolithography, reactive ion etching and anodization. A layer of patterned SiO_2 mask is introduced as resist on the surface of Al foil, and during anodization the tilted nanopores and remaining Al microstructure are formed underneath the SiO_2 mask. The existence of SiO_2 mask leads to the deflection of electric field and effect on the transportation of ions, which results in the formation of laterally tilted nanopores, while the nanopores go down directly when being far from the boundaries of SiO_2. The vertical and lateral anodization processes proceeding simultaneously construct the Al microstructure under the patterned SiO_2 mask.