Surface electric field and adsorption properties of noble metal modified graphene in methane gas

Based on COMSOL Multiphysics software, the geometric model of graphene structure is set on the two-dimensional plane, and the thickness of graphene layer is set at 400 nm. The real and imaginary parts of the refractive index of graphene are defined. Then, the Ag and Au films are coated on both sides of graphene to form the Ag/G/Ag and Au/G/Au sandwich structures, respectively. In addition, the electric field modes between 300 nm and 600 nm are obtained by parameterized scanning calculation of the incident wavelength λ. At the same time, adsorption, scattering and extinction spectra are plotted. Results indicated that the maximum field strength of both the Ag/G/Ag and Au/G/Au sandwich structures are nearly doubled as compared to the intrinsic graphene. Finally, the adsorption, scattering and extinction properties are discussed. It is concluded that the resonance absorption peaks can be adjusted and improved by Ag/Au modification. The strongest plasma resonance mode shifts towards high energy. Moreover, Ag/G/Ag has stronger surface plasmon resonance effect than that of Au/G/Au structure.