Study on the broad spectral absorption property of monolayer MoS₂ based on hybrid structures

School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing 210094, China and MIIT Key Laboratory of Thermal Control of Electronic Equipment, Nanjing University of Science and Technology Nanjing 210094, China

^(a) tanhongwh@njust.edu.cn

Received: 5 July 2019
Accepted: 5 November 2019

Abstract

The poor light absorption property in monolayer MoS₂ limits its applications such as in photonics, optoelectronics and energy utilizations. Here, we propose a hybrid structure, consisting of a Fabry-Perot (F-P) cavity, plasmonic silver (Ag) gratings and an Ag/Al₂O₃/Al gap-plasmon resonator, to improve the light absorption of monolayer MoS₂ in the wavelength region from 400 to 700 nm. We theoretically investigate the spectral absorption of monolayer MoS₂ placed on top of different hybrid structures by FDTD simulations. The simulation results show that monolayer MoS₂ in the MoS₂/Ag grating/Al₂O₃/Al structure can absorb about 27.6% of the incident solar light integrated from 400 to 700 nm. The absorption peaks can be tuned in a wide spectral range by changing the geometrical parameters of the structure. We further design Ag gratings with interlaced stripes to enhance the absorption from 500 to 700 nm. The proposed structures in this study also can be applied to other two-dimensional semiconductors to achieve strong absorption in the visible spectral region.