Dark exciton-exciton annihilation in monolayer WSe${}_2$

Abstract

The exceptionally strong Coulomb interaction in semiconducting transition-metal dichalcogenides (TMDs) gives rise to a rich exciton landscape consisting of bright and dark exciton states. At elevated densities, excitons can interact through exciton-exciton annihilation (EEA), an Auger-like recombination process limiting the efficiency of optoelectronic applications. Although EEA is a well-known and particularly important process in atomically thin semiconductors determining exciton lifetimes and affecting transport at elevated densities, its microscopic origin has remained elusive. In this joint theory-experiment study combining microscopic and material-specific theory with time- and temperature-resolved photoluminescence measurements, we demonstrate the key role of dark intervalley states that are found to dominate the EEA rate in monolayer WSe${}_2$. We reveal an intriguing, characteristic temperature dependence of Auger scattering in this class of materials with an excellent agreement between theory and experiment. Our study provides microscopic insights into the efficiency of technologically relevant Auger scattering channels within the remarkable exciton landscape of atomically thin semiconductors.

17 pages, 6 figures

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Cited by in corpus (15)

• Electrical control of hybrid exciton transport in a van der Waals heterostructure
• Exciton optics, dynamics and transport in atomically thin semiconductors
• Strain control of hybridization between dark and localized excitons in a 2D semiconductor
• Microscopic origin of anomalous interlayer exciton transport in van der Waals heterostructures
• Theoretical methods for excitonic physics in two-dimensional materials
• Probing correlations in the exciton landscape of a moiré heterostructure
• Ultrafast phonon-driven charge transfer in van der Waals heterostructures
• Leaky exciton condensates in transition metal dichalcogenide moiré bilayers
• Signatures of dark excitons in exciton-polariton optics of transition metal dichalcogenides
• Impact of optically pumped non-equilibrium steady states on luminescence emission of atomically-thin semiconductor excitons
• Excitonic thermalization bottleneck in twisted TMD heterostructures
• Wannier-Function-Based Approach to Coupled Exciton-Phonon-Photon Dynamics in Two-Dimensional Semiconductors
• Strain-Enabled Giant Second-Order Susceptibility in Monolayer WSe${}_2$
• Valley-controlled many-body exciton interactions in monolayer WSe${}_2$ phototransistors
• Universal fragmentation in annihilation reactions with constrained kinetics