Highly Enhanced Raman Scattering of Graphene using Plasmonic Nano-Structure

Highly enhanced Raman scattering of graphene on a plasmonic nano-structure platform is demonstrated. The plasmonic platform consists of silver nano-structures in a periodic array on top of a gold mirror. The gold mirror is used to move the hot spot to the top surface of the silver nano-structures, where the graphene is located. Two different nano-structures, ring and crescent, are studied. The actual Raman intensity is enhanced by a factor of 890 for the G-peak of graphene on crescents as compared to graphene on a silicon dioxide surface. The highest enhancement is observed for the G-peak as compared to the 2D-peak. The results are quantitatively well-matched with a theoretical model using an overlap integral of incident electric field intensities with the corresponding intensities of Raman signals at the G- and 2D-peaks. The interaction of light with nano-structures is simulated using finite element method (FEM).