Unveiling the optical emission channels of monolayer semiconductors coupled to silicon nanoantennas*

Monolayers (MLs) of transition metal dichalcogenides (TMDs) such as WSe₂ and MoSe₂ can be placed by dry stamping directly on broadband dielectric resonators, which have the ability to enhance the spontaneous emission rate and brightness of solid-state emitters at room temperature. We show strongly enhanced emission and directivity modifications in room temperature photoluminescence mapping experiments. By varying TMD material (WSe₂ versus MoSe₂) transferred on silicon nanoresonators with various designs (planarized versus non-planarized), we experimentally separate the different physical mechanisms that govern the global light emission enhancement. For WSe₂ and MoSe₂ we address the effects of Mie Resonances and strain in the monolayer. For WSe₂ an important additional contribution comes from out-of-plane exciton dipoles. This paves the way for more targeted designs of TMD -Si nanoresonator structures for room temperature applications.