Raman characteristics of graphene/quartz and graphene/Ag nanoparticles/quartz substrate: Laser power dependence

Abstract

The sensitivity of graphene surface to adjacent conditions plays an important role that modifies the performance and characteristics of graphene devices working under ambient conditions. Quartz is a dielectric transparent material with excellent optical transmission and therefore graphene/quartz is widely used in graphene device technology. Here, graphene/quartz and graphene/plasmonic nanoparticle/quartz structures were investigated using Raman spectroscopy for applications in nanotechnology like graphene quartz fiber (GQF) multifunctional electrode. Optically induced shift of the Fermi level of graphene monolayer on quartz substrates and on Ag nanoparticles (NPs) distributed on quartz substrates was tracked by increasing the applied laser power. Strained graphene attached to quartz substrate, thermal effects, and charge transfer were discussed using the evolution of the G-peak characteristics. Well distributed Ag NPs on quartz substrate are shown by scanning electron microscopy; an interesting property of plasmonic nanoparticles on quartz substrates. The graphene on single Ag NP verified using Raman mapping images by the surface enhanced Raman G-peak on the Ag NP. The Ag NP was driven to the plasmonic resonance by selecting the laser probe wavelength and the localized surface plasmons excited in Ag NPs were inferred by the transmission and photoluminescence spectra. Investigations of graphene on quartz and on plasmonic nanoparticles/quartz substrates can help for GQF hybrid structures which combines the enhanced thermal and electrical conductivity of graphene/plasmonic nanoparticles in addition to the extraordinary properties of quartz fibers suitable for sensing applications.