Resistless nanoimprinting in metal for plasmonic nanostructures

Metal nanostructures are the main building blocks of metamaterials and plasmonics which show many extraordinary properties not existing in nature. A simple and widely applicable method that can directly pattern metals with silicon molds without the need of resists, using pressures of <4 MPa and temperatures of 25-150 °C is reported. Three-dimensional structures with smooth and vertical sidewalls, down to sub-10 nm resolution, are generated in silver and gold films in a single patterning step. Using this nanopatterning scheme, large-scale vivid images through extraordinary optical transmission and strong surface-enhanced Raman scattering substrates are realized. Resistless nanoimprinting in metal (RNIM) is a new class of metal patterning that allows plasmonic nanostructures to be fabricated quickly, repeatedly, and at a low-cost.