Edge-engineered self-assembled hierarchical plasmonic SERS templates

Surface enhanced Raman scattering (SERS) has emerged as a reliable and ultra-sensitive sensing technique used in analytical diagnostics, forensics, and biomedical applications. Although SERS may be sensitive enough to detect single molecules, such extreme performance is achieved with sophisticated and complex nanostructure designs that are hard to implement on an industrial scale. This work presents an understanding of the plasmonic and wetting phenomena taking place on Ag nanoparticles (supported on Si) produced by laser annealing and dewetting of sputtered ultra-thin layers enabling the fast (<3 min), scalable and cost-effective production of SERS templates with a hierarchical plasmonic structure. In particular, the produced SERS templates incorporate micron-scale accumulation spots of the Rhodamine 6 G test molecules, superimposed over nano-scale hot spots, where electric near field enhancement occurs due to plasmon resonances. This combination increases drastically the SERS signal, making it suitable for fast chemical diagnostics.