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

TL;DR

This study investigates how monolayer TMD semiconductors like WSe2 and MoSe2, when coupled with silicon nanoantennas, exhibit enhanced and directed optical emission at room temperature, revealing physical mechanisms behind emission improvements.

Contribution

It experimentally separates physical mechanisms such as Mie resonances, strain, and out-of-plane dipoles affecting emission enhancement in TMD-silicon nanoresonator systems.

Findings

Enhanced emission and directivity observed in photoluminescence mapping.

Different physical mechanisms identified for WSe2 and MoSe2.

Out-of-plane exciton dipoles significantly contribute to emission in WSe2.

Abstract

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.