Au concentration‐dependent quenching of Raman 2D peak in graphene

We investigate the effect of sputtered gold nanoclusters (AuNCs) on the Raman spectra of graphene. The two prominent Raman peaks of graphene – 2D and G – show drastically different behaviour with AuNC introduction. The Raman 2D peak intensity decreases with gold coverage and finally is quenched for moderate gold nanoparticle coverage, while the G peak shows a AuNC size‐dependent enhancement in peak intensity. The quenching of the 2D peak is attributed to the hybridization of graphene's 2p z orbital with the 5d orbitals of Au. The G peak enhancement is due to the surface‐enhanced Raman scattering induced by the surface plasmons created in the AuNC by the incident laser beam (He–Ne laser, wavelength = 632.8 nm). The existence of surface plasmons is independently confirmed by UV‐visible spectrophotometry measurements. Copyright © 2017 John Wiley & Sons, Ltd.