Temperature dependent temporal coherence of metallic-nanoparticle-induced single-photon emitters in a WSe$_{2}$ monolayer

TL;DR

This study investigates the temperature-dependent coherence and emission properties of single-photon emitters in WSe₂ monolayers induced by metallic nanoparticles, revealing how temperature affects their quantum optical performance.

Contribution

It provides the first detailed analysis of temperature effects on the coherence time and decay dynamics of nanoparticle-induced single-photon emitters in WSe₂ monolayers.

Findings

Single-photon emission verified with g^{(2)}(0) = 0.036

Coherence time decreases from 13.5 ps at 4 K to 9 ps at 8 K

Decay time decreases from 2.4 ns to 0.42 ns with temperature

Abstract

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 WSe$_{2}$, 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 WSe$_{2}$ monolayer which are induced by metallic nanoparticles. Under quasi-resonant pulsed excitation, we verify clean single-photon emission with a $g^{(2)}(0) = 0.036\pm0.004$. Furthermore, we determine its temperature dependent coherence time via Michelson interferometry, where a value of (13.5$\pm$1.0) ps is extracted for the zero-phonon line (ZPL) at 4 K, which reduces to (9$\pm$2) ps at 8 K. Associated time-resolved photoluminescence experiments reveal a decrease of the decay time from (2.4$\pm$0.1) ns to (0.42$\pm$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.