▎ 摘　　要

In this work, a plasmonic metasurface for ultra-sensitive biosensing based on graphene-transition metal dichalcogenide (TMDC)-graphene hybrid nanostructures are designed. The coating of the two-dimensional nanosheets plays an important role for the sensitivity enhancement of the biosensors at the atomic scale. To achieve the maximum plasmon resonance energy transfer, different parameters of the hybrid nanostructures are systematically investigated including the material types and the number of TMDC layers. The important characteristics of plasmonic biosensors such as dark minimum reflectivity, sharp differential phase change, high sensitivity and narrow full width at half maximum (FWHM) are carefully studied in this work to demonstrate the improved surface plasmon resonance sensing performances of the TMDC-based metasurfaces. The graphene-TMDC-graphene configurations with four different types of materials including MoS2/WS2/MoSe2/WSe2 are optimized respectively for potential sensing applications. Based on our theoretical analysis, the enhanced maximum sensitivity of graphene-TMDC-graphene hybrid nanostructure is three orders of magnitude higher than that of the conventional bare metallic substrate.