Excitation-Dependent Emission Pathways in WSe₂ Single-Photon Emitters

Monolayer WSe₂ has emerged as a promising material platform for quantum light generation, hosting exciton-mediated single-photon emitters (SPEs) with its potential to be integrated with diverse on-chip photonic architectures. However, further progress has been limited by an incomplete understanding of the defect states and excitation mechanisms underlying single-photon emission. In this work, we employ photoluminescence excitation (PLE) spectroscopy to probe the excitation resonances of individual WSe₂ emitters while monitoring their emission characteristics. We identify a universal, broad absorption band near the neutral exciton energy, which we attribute to exciton funneling from the host monolayer into localized defect states. In addition to this common feature, each emitter exhibits a distinct set of lower-energy resonances that are highly sensitive to excitation conditions. Excitation at these resonances is found to strongly influence the photophysical response of the SPEs, including photon purity, emission lifetimes and intensity, revealing the interplay of exciton funneling, intermediary dark (grey) states, and local strain in governing the emission dynamics. By identifying these excitation-dependent mechanisms, our findings provide a pathway to optimize photon purity and emission properties for the integration of WSe₂ SPEs into photonic devices.