Self-assembled plasmonic nanoring cavity arrays for SERS and LSPR biosensing.

Self-assembled plasmonic nanoring cavity arrays are formed alongside the curvature of highly packed metallic nanosphere gratings. The sub-10-nm gap size is precisely tuned via atomic layer deposition and highly ordered arrays are produced over a cm-sized area. The resulting hybrid nanostructure boosts coupling efficiency of light into plasmons, and shows an improved SERS detection limit. These substrates are used for SERS detection of the biological analyte, adenine, followed by concurrent localized surface plasmon resonance sensing.