Quantifying Plasmon-Enhanced Light Absorption in Monolayer WS₂ Films

Transition metal dichalcogenide semiconductors hold great promise in photonic and optoelectronic applications, such as flexible solar cells and ultrafast photodetectors, because of their direct band gap and few-atom thicknesses. However, it is crucial to understand and improve the absorption characteristics of these monolayer semiconducting materials. In this study, we conducted a systematic numerical and experimental investigation to demonstrate and quantify absorption enhancement in WS₂ monolayer films, in the presence of silver plasmonic nanodisk arrays. Our analysis combining full-field electromagnetic simulations and optical absorption spectroscopy measurements indicates a fourfold enhancement in the absorption of an WS₂ film near its band edge, close to the plasmonic resonance wavelength of Ag nanodisk arrays. The proposed Ag/WS₂ heterostructure exhibited a 2.5-fold enhancement in calculated short-circuit current. Such hybrid plasmonic or two-dimensional (2D) materials with enhanced absorption pave the way for the practical realization of 2D optoelectronic devices, including ultrafast photodetectors and solar cells.