Fabrication of Large-Area Self-Organizing Gold Nanostructures with Sub-10 nm Gaps on a Porous Al2O3 Template for Application as a SERS-Substrate

Abstract

A new technique for fabrication of large-area self-organizing variably ordered gold nanostructures with sub-10 nm gaps on templates of hexagonally ordered porous anodic aluminum oxide is demonstrated. The size as well as the interparticle distance of the fabricated gold nanostructures are adjusted by application of various electrolytes used in anodization of the aluminum template and the thickness of gold sputter-coated on the pore layer. The fabricated substrates are characterized by SEM and optical extinction measurements in reflection. The applicability as SERS substrates is investigated by adsorption of rhodamine 6G on the nanostructures. These substrates are found to exhibit high and uniform enhancement of the Raman signal across the entire surface. The nanostructures can be utilized as low-cost SERS-active substrates that within a short time can be fabricated reproducibly in large amounts.