In recent years, much research has been undertaken to investigate the suitability of two-dimensional materials to act as single-photon sources with high optical and quantum optical quality. Amongst them, transition-metal dichalcogenides, especially WSe2, have been one of the subjects of intensive studies. Yet, their single-photon purity and photon indistinguishability, remain the most significant challenges to compete with mature semiconducting systems such as self-assembled InGaAs quantum dots. In this work, we explore the emission properties of quantum emitters in a WSe2 monolayer which are induced by metallic nanoparticles. Under quasi-resonant pulsed excitation, we verify clean single-photon emission with a g(2)(0)=0.036±0.004. Furthermore, we determine its temperature dependent coherence time via Michelson interferometry, where a value of (13.5±1.0) ps is extracted for the zero-phonon line (ZPL) at 4 K, which reduces to (9±2) ps at 8 K. Associated time-resolved photoluminescence experiments reveal a decrease of the decay time from (2.4±0.1) ns to (0.42±0.05) ns. This change in decay time is explained by a model which considers a F\"orster-type resonant energy transfer process, which yields a strong temperature induced energy loss from the SPE to the nearby Ag nanoparticle.
@article{arxiv.2307.07282,
title = {Temperature dependent temporal coherence of metallic-nanoparticle-induced single-photon emitters in a WSe$_{2}$ monolayer},
author = {Martin von Helversen and Lara Greten and Imad Limame and Chin-Wen Shih and Paul Schlaugat and Carlos Antón-Solanas and Christian Schneider and Bárbara Rosa1 and Andreas Knorr and Stephan Reitzenstein},
journal= {arXiv preprint arXiv:2307.07282},
year = {2023}
}