Integration of highly ordered nanoporous anodic alumina templates on substrates for nanofabrication

Highly ordered porous anodic alumina (HOPAA) is directly fabricated on the various substrates over large areas (> 1.5 cm²) by using a "soft-imprinting" method. In this process, we employ Ar plasma etching to "soft imprint" an evaporated Al film through a free-standing HOPAA mask. The nanoindentation arrays replicated from the mask and created on the Al surface by soft imprinting will guide the subsequent Al anodization to form HOPAA templates on the substrate (HOPAA/substrate). This technique allows for fabricating the HOPAA template on the different substrates, such as Si, glass slide, and even flexible polymer films. Compared with conventional techniques for HOPAA, our technique is substrate-friendly and cost-effective for fabricating HOPAA/substrate. The intimate contact between the template and the substrate enables solution-based fabrication. We demonstrate that the HOPAA/substrate can be used to create highly ordered Au nanowire arrays on Si.