Plasmonic image reproduction with solid-state superionic stamping (S4)

Traditional top-down approaches for producing metallic nanostructures, despite being capable of producing arbitrary 2-D shapes, often use vacuum-based deep sub-micron lithographic fabrication technologies. This makes their use for single-use devices like chemical and bio-sensing substrates difficult to economically justify. Here, the authors demonstrate a manufacturing pathway that only uses such techniques to produce a master. This reusable master, coupled with a unique and facile electrochemical imprinting process, Solid-State Superionic Stamping (S4), is used to produce several replicated metallic nanostructures, thus demonstrating an economically feasible manufacturing pathway for single-use, nano-enabled devices.

This paper uses plasmonic image reproduction as an easy-to-visualize proxy for single-use devices such as plasmonic sensors and Surface Enhanced Raman Spectroscopy (SERS) substrates that require nanopatterned metallic structures. It demonstrates a process for replicating a picture by a set of metallic structures that plasmonically produce the desired colors locally. It uses a digitizing computational tool, direct-write Two-Photon Lithography (TPL) and a dry-etch process to rapidly produce a silicon master. This master is used to hot emboss nano-patterns in superionic glass blanks that, in turn, are used for electrochemical imprinting with S4 to reproduce the patterns on Ag substrates. The different steps in this process flow are described along with their role and effectiveness in contributing to a high-fidelity plasmonic image reproduction.