Enhanced light-matter interaction of a MoS2 monolayer with a gold mirror layer

Abstract

MoS2 monolayer is a member of transition metal dichalcogenides (TMDs), which has shown great potential for applications in light-emitting devices due to a direct band gap in its electronic structure. However, a region of atmomic thickness remains a challenge due to its weak light-matter interaction. Most approaches to improve the light-matter interaction of MoS2 have been devoted to plasmonic nanostructures and photonic crystal. Herein, we demonstrated a method based on the insertion of a gold mirror layer between the dielectric layer and the substrate to enhance the optical absorption and emission of the MoS2 monolayer. The hybrid nanostructure comprised a 35 nm SiO2 dielectric spacer and 40 nm golden film. The overall photoluminescence intensity was amplified nearly 4 times, resulting from enhanced optical absorption and Fabry-Perot cavity reflection. We further demonstrated that the improvement in the PL intensity can also be modulated by selecting a spacer material and changing the layer thickness. This study is broadly applicable to enhance the light-matter interaction of TMDs for applications in potential devices such as light-emitting devices, lasers, and photodetectors.