Fabrication and characterization of a dual-mode SPR/SERS sensor based on plasmonic nanodome arrays

This work describes a label-free, optical sensor system fabricated on a flexible plastic film with dual detection modalities: surface-enhanced Raman scattering (SERS) for specific chemical identification and localized surface plasmon resonance (LSPR) for capture-affinity biosensing. The sensor surface is comprised of a close-packed array of 383 nm diameter dome structures with interdome spacing of 14 nm, fabricated by a nanoreplica molding process and unpatterned blanket deposition of SiO₂ and Ag thin films. The nanoreplica molding process presented in this work allows for simple, high-throughput fabrication of uniform nanoscale structures (nanodome arrays) over large surface areas without the requirement for high resolution lithography, additional processes such as etching and liftoff, or defect-free deposition of spherical microparticle monolayer templates. Such fabrication characteristics are important for realizing high performance, low-cost measurement technology.