Single photon emission in $WSe_2$ up 160 K by quantum yield control

Abstract: Two dimensional semiconductors hosting strain-induced quantum emitters offer unique abilities to achieve scalable architectures for deterministic coupling to nanocavities and waveguides that are required to enable chip-based quantum information processing technologies. A severe drawback remains that exciton emission from quantum emitters in $WSe_2$ quenches beyond 30 K, which requires cryogenic cooling. Here we demonstrate an approach to increase the temperature survival of exciton quantum emitters in $WSe_2$ that is based on maximizing the emitter quantum yield. Utilizing optimized material growth that leads to reduced density of nonradiative defects as well as coupling of the exciton emission to plasmonic nanocavities modes, we achieve average quantum yields up to 44%, thermal activation energies up to 92 meV, and single photon emission signatures up to temperatures of 160 K. At these values non-cryogenic cooling with thermo-electric chips becomes already feasible, while quantitative analysis shows that room temperature operation is within reach through active strain engineering.