Fig. 1. Monolayer WS₂/Gr vdWhs-Au NC coupled system. (a) A schematic of the coupled system with an Au NC and a monolayer WS₂/Gr vdWhs. (b) Bright-field and (c) SEM images of the Au NC. The white dashed circle indicates the Au NC measured in the optical setups. (d) Zoom-in SEM image of the corresponding individual Au NC. The scale bar is 100 nm. (e) Raman spectra of the monolayer WS₂/Gr vdWhs (blue solid lines).

Fig. 2. Optical characterization of the monolayer WS₂/Gr vdWhs-Au NC. (a) Scattering spectra of Au NC uncoupled (upper panel) and coupled with monolayer WS₂/Gr vdWhs flakes (lower panel). The inset shows the charge distributions of the plasmon mode. (b) Electromagnetic field enhancement maps of the Au NC (length 87 nm). (c) PL spectra of WS₂/Gr vdWhs (orange solid line) and monolayer WS₂ (blue solid line). (d) Mode volume of the Au NC when coupled with the WS₂/Gr vdWhs (orange squares) and the WS₂ (blue squares).

Fig. 3. Experimental dark-field scattering spectra of the Au NC with an increased alumina coating.

Fig. 4. Strong coupling in the monolayer WS₂/Gr vdWhs-Au NC. (a) Experimental and (b) simulated dark-field scattering spectra of the coupled system with an increased alumina coating.

Fig. 5. Anticrossing behavior of the monolayer WS₂/Gr vdWhs-Au NC and WS₂-Au NC. Energy of the UPB (orange dots) and LPB (blue dots) as a function of detuning for (a) WS₂/Gr vdWhs-Au NC and (b) WS₂-Au NC coupled systems. The green dots denote the exciton energy, and the purple dots represent the plasmon energy. Hopfield coefficients for the UPB (upper panels) and LPB (lower panels) of the (c) WS₂/Gr vdWhs-Au NC and (d) WS₂-Au NC coupled systems. Fitted (solid curves) and experimental (dots) spectral widths of the UPB and LPB for the (e) WS₂/Gr vdWhs-Au NC and (f) WS₂-Au NC coupled systems.