Enhancement of absorption of molybdenum disulfide monolayer on low-index contrast dielectric grating in the visible regions

A design consists of low-index contrast grating is proposed to achieve the narrow absorption response for two-dimensional (2D) materials such as a MoS2 monolayer in the visible wavelength regime. High absorption occurs at the wavelength of Fano resonance for both transverse dielectric (TE) and transverse magnetic (TM) polarizations. It is proved that by manipulating related structural parameters and the incident angle, the peak wavelengths of MoS2 absorption can be tuned in a wide range. In addition, an improved structure with MoS2 ribbons is proposed to further boost the light-MoS2 interaction. The relationships between the absorptance and the period and width of MoS2 ribbons are discussed. The proposed optical devices could be efficiently exploited as tunable absorbing structures for optoelectronics and photovoltaic devices in the visible region.