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There is an increasing interest in using monolayer molybdenum disulfide (MoS 2 ) for optoelectronic devices because of its inherent direct band gap characteristics. However, the weak absorption of monolayer MoS 2 restricts its applications, novel concepts need to be developed to address the weakness. In this work, monolayer MoS 2 monolithically integrates with plane microcavity structure, which is formed by the top and bottom chirped distributed Bragg reflector (DBR), is demonstrated to improve the absorption of MoS 2 . The optical absorption is 17-fold enhanced, reaching values over 70% at work wavelength. Moreover, the monolayer MoS 2 -based photodetector device with microcavity presents a significantly increased photoresponse, demonstrating its promising prospects in MoS 2 -based optoelectronic devices. [ABSTRACT FROM AUTHOR]

A novel structure with bilayer hybrid graphene/metal (G/M) gratings to realize tunable double Fano resonances has been proposed. Different band gaps can be obtained by applying voltages on the bilayer graphenes. Due to the tunability of the hybrid structure, two different resonances are separately tuned under various parametric conditions. The Fano resonances are produced by the interaction between the metal and graphene gratings, the related mechanism is investigated by the electric field distribution and transmission phase. The superior characteristics of the separately tunable double Fano resonances indicate a promising application in THz optical devices. [ABSTRACT FROM AUTHOR]

A hybrid novel structure of monolayer WS 2 with Ag nanograting and distributed Bragg reflector (DBR) on Si substrate has been proposed to obtain broad-band absorption response for two-dimensional (2D) materials. It is effective to reduce light loss and reflect the incident light efficiently for monolayer WS 2 absorption with DBR dielectric layers. Moreover, by combining Ag nanograting with DBR structure, the average absorption achieves as high as 52.9% within broad wavelength ranging from 420 to 700 nm, which is attributed to the plasmonic resonant effect of metal nanostripes. The absorption would be influenced by the period and height of the Ag nanograting, and shows incident angle dependent characteristics, while an average absorption higher than 50% has been obtained at the incident angle around 40°. These results indicate that 2D WS 2 in combination with DBR and metal nanograting have a promising potential applications for optical nano-devices. [ABSTRACT FROM AUTHOR]