Irradiation of Nanostrained Monolayer WSe$_2$ for Site-Controlled Single-Photon Emission up to 150 K

TL;DR

This study introduces a novel strain and defect engineering method in monolayer WSe$_2$ that creates site-specific single-photon emitters functioning up to 150 K, advancing quantum light source technology.

Contribution

The paper presents a new approach combining nanoscale stressors and electron-beam irradiation to achieve high-yield, site-controlled single-photon emitters in WSe$_2$ operating at elevated temperatures.

Findings

Emitters exhibit exciton-biexciton cascaded emission.

Purity levels exceed 95%.

Operational temperature reaches 150 K.

Abstract

Quantum-dot-like WSe$_2$ single-photon emitters have become a promising platform for future on-chip scalable quantum light sources with unique advantages over existing technologies, notably the potential for site-specific engineering. However, the required cryogenic temperatures for the functionality of these sources have been an inhibitor of their full potential. Existing strain engineering methods face fundamental challenges in extending the working temperature while maintaining the emitter's fabrication yield and purity. In this work, we demonstrate a novel method of designing site-specific single-photon emitters in atomically thin WSe$_2$ with near-unity yield utilizing independent and simultaneous strain engineering via nanoscale stressors and defect engineering via electron-beam irradiation. Many of these emitters exhibit exciton-biexciton cascaded emission, purities above 95%, and working temperatures extending up to 150 K, which is the highest observed in van der Waals semiconductor single-photon emitters without Purcell enhancement. This methodology, coupled with possible plasmonic or optical micro-cavity integration, potentially furthers the realization of future scalable, room-temperature, and high-quality van der Waals quantum light sources.