Structure-Dependent Dynamics of Quantum Emitters in Single-Layer WSe₂.

Abstract

Single-layer WSe₂ hosts localized states that are technologically promising solid-state quantum light sources. Their formation requires localized tensile strain and is robust to substrate, material quality, and nanoscale stressors. How these factors affect the quantum emitters is obscured by intrasample heterogeneity that hinders the comparison of individual emitters across different samples. Here, by statistically comparing emitter populations from samples with unique permutations of material quality, substrate composition, and nanoscale stressors, we show that sample architecture affects emitter dynamics at the ensemble level. Systematic differences are revealed by formulating simple numerical descriptors of emitter photoluminescence transients from the different populations. Whereas the substrate does not significantly alter emitter dynamics, both nonlinear relaxation and exciton diffusion to emitter sites are reduced in high-quality WSe₂ on gold nanocones. This study demonstrates how statistical comparisons can reveal important structure-property relationships of the emitters that are important for further developing them into quantum light sources.