Gold on graphene as a substrate for surface enhanced Raman scattering study

Abstract

In this paper, we report our study on gold(Au)films with different thicknesses deposited on single layer graphene (SLG) as surface enhanced Raman scattering(SERS) substrates for the characterization of rhodamine (R6G) molecules. We find that an Aufilm with a thickness of ∼ 7 nm deposited on SLG is an ideal substrate for SERS, giving the strongest Raman signals for the molecules and the weakest photoluminescence(PL) background. While Aufilms effectively enhance both the Raman and PL signals of molecules, SLG effectively quenches the PL signals from the Aufilm and molecules. The former is due to the electromagnetic mechanism involved while the latter is due to the strong resonance energy transfer from Au to SLG. Hence, the combination of Aufilms and SLG can be widely used in the characterization of low concentration molecules with relatively weak Raman signals.