Enhanced Directional Emission from Monolayer WSe2 Integrated onto a Multiresonant Silicon-Based Photonic Structure

Abstract

Two-dimensional transition-metal dichalcogenides such as WSe2 show great promise as versatile atomic-scale light sources for on-chip applications due to their advanced optoelectronic properties and compatibility with a silicon photonics platform. However, the sub-nanometer thickness of such active materials limits their emission efficiency. Hence, new approaches to simultaneously enhance the emission and control its directionality are required. Here, we demonstrate enhanced and directional emission from a WSe2 monolayer integrated onto a silicon photonic structure. This is achieved by coupling of the WSe2 layer to a multiresonant silicon grating-waveguide structure. The interaction with the multiple resonant modes supported by the structure provides simultaneous excitation and emission enhancement, while the dispersion of the modes further routes the emission into specified directions. In addition, our hybrid structure offers the opportunity for ultrafast emission modulation, owing to the reduced emission lifetime of WSe2. Such a silicon-based hybrid platform is fully scalable and promising as efficient chip-integrated and spatially multiplexed light sources.