title: Large-area, freestanding, single-layer graphene-gold: a hybrid plasmonic nanostructure.
abstract: Graphene-based plasmonic devices have recently drawn great attention. However, practical limitations in fabrication and device architectures prevent studies from being carried out on the intrinsic properties of graphene and their change by plasmonic structures. The influence of a quasi-infinite object (i.e., the substrate) on graphene, being a single sheet of carbon atoms, and the plasmonic device is overwhelming. To address this and put the intrinsic properties of the graphene-plasmonic nanostructures in focus, we fabricate large-area, freestanding, single-layer graphene-gold (LFG-Au) sandwich structures and Au nanoparticle decorated graphene (formed via thermal treatment) hybrid plasmonic nanostructures. We observed two distinct plasmonic enhancement routes of graphene unique to each structure via surface-enhanced Raman spectroscopy. The localized electronic structure variation in the LFG due to graphene-Au interaction at the nanoscale is mapped using scanning transmission X-ray microscopy. The measurements show an optical density of ∼0.007, which is the smallest experimentally determined for single-layer graphene thus far. Our results on freestanding graphene-Au plasmonic structures provide great insight for the rational design and future fabrication of graphene plasmonic hybrid nanostructures.
authors.affiliation: Canadian Light Source , 44 Innovation Boulevard, Saskatoon, SK S7N 2V3, Canada.
authors.forename: Ganjigunte R Swathi
authors.initials: GR
authors.lastname: Iyer
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Garth
authors.initials: G
authors.lastname: Wells
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Guruvenket
authors.forename: Scott
authors.initials: S
authors.lastname: Payne
authors.forename: Michael
authors.initials: M
authors.lastname: Bradley
authors.forename: Ferenc
authors.initials: F
authors.lastname: Borondics
mesh_terms: D002244:Carbon / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D055095:Optics and Photonics; D013059:Spectrum Analysis, Raman; D020349:Surface Plasmon Resonance; D013696:Temperature
chemical_list: D002244:Carbon; D006046:Gold; D006108:Graphite