title: Surface enhanced Raman scattering of gold nanoparticles supported on copper foil with graphene as a nanometer gap.
abstract: Gaps with single-nanometer dimensions (<10 nm) between metallic nanostructures enable giant local field enhancements for surface enhanced Raman scattering (SERS). Monolayer graphene is an ideal candidate to obtain a sub-nanometer gap between plasmonic nanostructures. In this work, we demonstrate a simple method to achieve a sub-nanometer gap by dewetting a gold film supported on monolayer graphene grown on copper foil. The Cu foil can serve as a low-loss plasmonically active metallic film that supports the imaginary charge oscillations, while the graphene can not only create a stable sub-nanometer gap for massive plasmonic field enhancements but also serve as a chemical enhancer. We obtained higher SERS enhancements in this graphene-gapped configuration compared to those in Au nanoparticles on Cu film or on graphene-SiO2-Si. Also, the Raman signals measured maintained their fine features and intensities over a long time period, indicating the stability of this Au-graphene-Cu hybrid configuration as an SERS substrate.
authors.affiliation: School of Physics and Electronics, State Key Laboratory for Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Xiang
authors.forename: Xupeng
authors.initials: X
authors.lastname: Zhu
authors.forename: Yiqin
authors.initials: Y
authors.lastname: Chen
authors.forename: Huigao
authors.initials: H
authors.lastname: Duan