Fabrication of sub-20 nm nano-gap structures through the elastomeric nano-stamp assisted secondary sputtering phenomenon

We describe a highly efficient method for fabricating controllable and reliable sub-20 nm scale nano-gap structures through an elastomeric nano-stamp with an embedded ultra-thin pattern. The stamp consists of ultrahigh resolution (approximately 10 nm) and high aspect ratio (ca. 15) metal nano-structures, which are obtained by secondary sputtering lithography (SSL). The nano-gap structures fabricated in this fashion achieve a high resolution and meet the requirements of minimal cost, high reliability, controllability, reproducibility, and applicability to different materials. Further, we demonstrate that this method enables the fabrication of SERS substrates for detection at the single-molecule level.