Enhanced light-matter interaction in graphene-covered gold nanovoid arrays

TL;DR

This paper demonstrates a novel hybrid graphene-gold nanovoid system that significantly enhances light-matter interactions, enabling improved sensing and potential single-molecule detection through strong plasmonic coupling and Raman signal amplification.

Contribution

Introduces a new hybrid graphene-metal nanostructure with resonances in the visible range, showing enhanced light absorption and Raman response, supported by experiments and simulations.

Findings

Over 30% light absorption in a single graphene layer

Up to 700-fold Raman enhancement of graphene

Potential for single-molecule SERS detection

Abstract

The combination of graphene with noble-metal nanostructures is currently being explored for strong light-graphene interaction enhanced by plasmons. We introduce a novel hybrid graphene-metal system for studying light-matter interactions with gold-void nanostructures exhibiting resonances in the visible range. Strong coupling of graphene layers to the plasmon modes of the nanovoid arrays results in significant frequency shifts of the underlying plasmon resonances, enabling more than 30% absolute light absorption in a single layer of graphene and up to 700-fold enhancement of the Raman response of the graphene. These new perspectives enable us to verify the presence of graphene on gold-void arrays and the enhancement even allows us to accurately quantify the number of layers. Experimental observations are further supported by numerical simulations and perturbation-theory analysis. The graphene gold-void platform is beneficial for sensing of molecules and placing R6G dye molecules on top of the graphene, we observe a strong enhancement of the R6G Raman fingerprints. These results pave the way toward advanced substrates for surface-enhanced Raman scattering (SERS) with potential for unambiguous single-molecule detection on the atomically well-defined layer of graphene.