| Compared with conventional noble metal plasmons,graphene plasmons provide better electromagnetic confinement,lower loss and dynamic surface plasmon resonance tunability,which are beneficial for various applications such as signal processing,light modulation,nonlinear photonics,and infrared sensing.Surface plasmons of grapheme nanostructures can be directly excited by bulk light.However,surface plasmons of intrinsic graphene nanostructures,including nanoribbons,nanodots and nanorings,exhibit the limitations of narrow resonance peak and low enhancement factor.Theoretical research shows that the hybrid nanostructures of graphene and metal have the advantage of enhanced light-matter interactions by confining the optical fields below the diffraction limit to help improving the eff-iciency of surface plasmonic device.The hybrid nanostructures of graphene and metal are useful not only for exploring the surface plasmonic properties of graphene but also for creating functional structures such as plasmon-enhanced photodetectors,sensors,and solar cells.In particular,the surface-enhanced infrared spectroscopy based on graphene plasmons can be used for sensing applications with high sensitivities.This article aims to construct grapheme film-metal nanoparticles(NPs)hybrid nanostructure,and explore the influence of metal nanoparticles on the doping and optical properties of grapheme film.By designing graphene nanostructure array(GNA)-metal nanoparticles hybrid nanostructure,the influence of metal nanoparticles on the graphene plasmonic properties is also investigated.The results are summarized as follow:1.We have developed a nano-metal film doping method to adjust graphene's conduction type.Large-area(centimeter scale)uniform n-doped graphene with a nanoscale smooth(RMS roughness?1.4 nm)has been obtained by thermal deposition of Ag nano-film on a transferred CVD graphene.The doping method is simple but effective.The Ag-doped graphene also exhibited large absorption coefficient(a>105 cm-1)at?500 nm,which makes it useful for various applications particularly as potential candidate in the optoelectronics.Our graphene doping method paves the way for graphene based optoelectronic devices.2.We have demonstrated the fabrication of AuNPs-GNA hybrid nanostructure with the aid of the block copolymer self-assembly method and a rapid thermal annealing.The dipole resonance of the graphene plasmon appeared in the mid-IR region,and the introduction of AuNPs led to a stiffer and broader graphene plasmon resonance peak.By utilizing the hybrid plasmonic structures as the substrate for plasmon-enhanced infrared spectroscopy,we observed 10-fold signal enhancement and the sensitive detection of the sub-monolayer PEO molecules was achieved.At the same time,the enhancement of the hybrid structure exists in a broader wavelength range compared with GNA,which can have safety and health related biological and chemical sensing potentials.3.By using finite difference time domain(FDTD)method,the relationship between GNA Fermi level and plasmonic properties is investigated.It is demonstrated that the plasmonic properties of GNA can be varied by changing the Fermi level.By introducing AuNPs to GNA,the position and width of plasmonic resonance peak can be tuned and the tuning effect highly depends on the AuNPs position.4.Two-dimensional nanomaterials(copper chalcogenides)other than graphene were successfully synthesized by a facile solvothermal method.When using ethylene glycol as solvent,the composition of the samples was controlled by changing the molar ratio of copper and selenium source.Finally,the band gaps of the hexagonal CuSe and the orthorhombic Cu2Se samples are estimated to be 1.73 eV and 1.91 eV,respectively.It has been found that this material exhibits a broad direct band-gap absorption in the visible region and a strong absorption tail in the near-infrared region attributed to the surface plasmons. |
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