Direct imprint of nanostructures in metals using porous anodic alumina stamps

A single-step nanoimprint process for direct patterning of metallic nanostructures at room temperature is described. Porous anodic alumina (PAA) is used for stamps and the structure can be optimized by adjusting the PAA fabrication parameters. The periodic hexagonal cells on the PAA stamps are transferred to the metals by mechanically pressing the stamps into the substrate, and various metal nanopatterns with different hardnesses and elastic moduli such as Sn, Zn, Al, Ag, Mg and Cu are fabricated. Metal nanopits or nanoislands with well defined spacing between 75 and 150 nm can be readily produced using the metal direct imprinting process. The mechanical properties of the PAA stamps and effects of imprinting pressure on the height of the transferred patterns are also investigated.