Fabrication of patterned and non-patterned metallic nanowire arrays on silicon substrate

Patterned micropads, 50 micrometer (μm) in diameter, comprising of multiple metallic nanowires are fabricated directly on a silicon substrate. Nanoporous alumina membrane that is used as a template for electrodeposition of nanowires is synthesized by potentiostatic anodization of a thin film of aluminum. For patterned nanoporous film growth, prior to anodization the thin film of aluminum is patterned with SiO2 that acts as an effective barrier to anodization. Nanopore diameter for the patterned thin film is varied from 39 to 150 nm by varying the anodization voltage from 20 to 195 V. The patterned nanoporous alumina thin film that is anodized at 60 V and is 1 μm thick is used as a template for electrodeposition of nickel nanowires. Nickel nanowires that are ∼ 5 μm long are also fabricated on a silicon substrate using a thicker alumina film as an electrodeposition template.