Wavelength-Selective Wide-Angle Light Absorption Enhancement in Monolayers of Transition-Metal Dichalcogenides

The monolayers of the transition-metal dichalcogenides (TMDs) supported by a periodic metal nano-groove array with a dielectric spacer are investigated both theoretically and numerically. Numerical results exhibit that an original Fabry-Perot resonance in the nanogroove enables the high-efficiency absorption of light (up to 61.48%) in monolayer molybdenum disulfide (MoS2) and the realization of a near-unity absorber in the visible region. The small changes in the structural parameters of nanogrooves give rise to the advantageous tunability of the wavelength of the absorption peak. Simulated results are in an excellent agreement with theoretical analysis. Intriguingly, such high-absorption of light in monolayer MoS2 remains unchanged over a wide angular range of incidence around +/- 70 degrees, and the high-enhancement of light absorption in the monolayers of molybdenum diselenide and tungsten diselenide is also obtained handily by using the same metal nano-groove array. Reported results should be useful for the TMDs-based photodetectors, the electro-optic modulators, and the light emission devices. These findings will open up new possibilities for improving the light-matter interaction in the burgeoning two-dimensional layered materials and heterostructures.