WS2 Monolayers Coupled to Hyperbolic Metamaterial Nanoantennas: Broad Implications for Light–Matter-Interaction Applications

Abstract

Due to their atomic layer thickness, direct bandgap, mechanical robustness and other superior properties, transition metal dichalcogenides (TMDCs) monolayers are considered as an attractive alternative to graphene for diverse optoelectronic applications. Yet, due to the very nature of atomic layer thickness, the interaction of light with TMDCs is limited, hindering overall efficiency for optical applications. Therefore, in order for TMDCs to become a true candidate as the material of choice for optoelectronics, there is a need for a mechanism which significantly enhances the interaction of light with TMDCs. In this paper, we demonstrate about 30-fold enhancement of the overall photoluminescence emission intensity from a WS2 monolayer, by its coupling to a hyperbolic metamaterial nanoantenna array. This enhancement corresponds to nearly 300-fold enhancement per individual nanoantenna. This overall enhancement is achieved by the combination of enhancing the excitation (absorption) efficiency, alongside with enhancing the radiative decay rate. Our result paves the way for the use of TMDCs in diverse optoelectronic applications, ranging from light sources and photodetectors to saturated absorbers and nonlinear media.