Well-ordered self-assembled plasmonic dimers for surface-enhanced Raman scattering

Abstract

Surface-enhanced Raman scattering (SERS) using structures of metal nanoparticles (NPs) is extremely sensitive to the relative orientation of the polarization of the incident light with the interparticle axis. Self-assembly of metal nanoparticles is a well-known approach to fabricate nanostructures. However, controlling the assembly direction of the NPs in this method is difficult. In this Letter, we propose a controlled self-assembly method using vacuum ultraviolet (VUV) light. By illuminating the surface-functionalized NPs with VUV light, the functionality is cancelled out, and therefore, we can select desirable direction of assembly. In the light of this method, well-ordered dimers (WODs) of silver NPs are fabricated. The Raman enhancement factor of WODs is about twice larger than randomly ordered ones.