Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas

TL;DR

This study demonstrates that coupling monolayer WSe2 to gallium phosphide dielectric nano-antennas significantly enhances quantum efficiency and brightness of single photon emitters, advancing quantum light source technology.

Contribution

It introduces a novel integration of 2D semiconductors with dielectric nano-antennas, achieving high brightness and efficiency in single photon emission.

Findings

Up to 10^4 times brighter photoluminescence compared to SiO2 pillars.

Quantum efficiency increased by a factor of 5 due to nano-antenna coupling.

Insights into photoluminescence dynamics, dark exciton, and Auger processes.

Abstract

Single photon emitters in atomically-thin semiconductors can be deterministically positioned using strain induced by underlying nano-structures. Here, we couple monolayer WSe$_2$ to high-refractive-index gallium phosphide dielectric nano-antennas providing both optical enhancement and monolayer deformation. For single photon emitters formed on such nano-antennas, we find very low (femto-Joule) saturation pulse energies and up to 10$^4$ times brighter photoluminescence than in WSe$_2$ placed on low-refractive-index SiO$_2$ pillars. We show that the key to these observations is the increase on average by a factor of 5 in the quantum efficiency of the emitters coupled to the nano-antennas. This further allowed us to gain new insights into their photoluminescence dynamics, revealing the roles of the dark exciton reservoir and Auger processes. We also find that the coherence time of such emitters is limited by intrinsic dephasing processes. Our work establishes dielectric nano-antennas as a platform for high-efficiency quantum light generation in monolayer semiconductors.