Fig. 1

Schematic diagram of RhB SM-SERS Raman detection. The golden sphere on the top refers to the attached Au nanoparticle. The green region below is the hot spot of excitation laser. The black (carbon), mazarine (nitrogen) and red (oxygen) ball-and-stick model presents the RhB molecule. The yellow (sulfur) and violet (tungsten) ball-and-stick model shows the mono-layer WS₂. The blue flash pattern illustrates the charge transfer between the RhB molecule and mono-layer WS₂. The subjacent cuboid shows the silicon slice with several coatings