A patterned array of metallic nanostructures and fabrication thereof is described. A plurality of nanowires is grown on a substrate, the plurality of nanowires being laterally arranged on the substrate in a predetermined array pattern. The plurality of nanowires is coated with a metal to generate a plurality of metal-coated nanowires. Vacancies between the metal-coated nanowires are filled in with a sacrificial material for stabilization, and the metal-coated nanowires are planarized. The sacrificial material is removed, the patterned array of metallic nanostructures being formed by the plurality of planarized metal-coated nanowires.