Direct Measurement of Biexcitons in Monolayer WS2

Abstract

The optical properties of atomically thin transition metal dichalcogenides (TMDCs) are dominated by Coulomb bound quasi-particles, such as excitons, trions, and biexcitons. Due to the number and density of possible states, attributing different spectral peaks to the specific origin can be difficult. In particular, there has been much conjecture around the presence, binding energy and/or nature of biexcitons in these materials. In this work, we remove any ambiguity in identifying and separating the optically excited biexciton in monolayer WS2 using two-quantum multidimensional coherent spectroscopy (2Q-MDCS), a technique that directly and selectively probes doubly-excited states, such as biexcitons. The energy difference between the unbound two-exciton state and the biexciton is the fundamental definition of biexciton binding energy and is measured to be 26 \pm 2 meV. Furthermore, resolving the biexciton peaks in 2Q-MDCS allows us to identify that the biexciton observed here is composed of two bright excitons in opposite valleys.

References in corpus (23)

• Atomically thin MoS2: A new direct-gap semiconductor
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Exciton Binding Energy of Monolayer WS2
• Photo-Induced Bandgap Renormalization Governs the Ultrafast Response of Single-Layer MoS2
• Identification of excitons, trions and biexcitons in single-layer WS2
• Binding energies of exciton complexes in transition metal dichalcogenides and effect of dielectric environment
• Revealing the Biexciton and Trion-exciton Complexes in BN Encapsulated WSe2
• Neutral and Charged Inter-Valley Biexcitons in Monolayer MoSe${}_2$
• Intervalley biexcitons and many-body effects in monolayer MoS2
• Phonon Sidebands in Transition Metal Dichalcogenides
• Coulomb-bound four- and five-particle valleytronic states in an atomically-thin semiconductor
• Electroluminescence from multi-particle exciton complexes in transition metal dichalcogenide semiconductors
• Biexciton fine structure in monolayer transition metal dichalcogenides
• Many-body two-quantum coherences in semiconductor nanostructures
• Optical properties of charged excitons in two-dimensional semiconductors
• Zeeman Splitting and Inverted Polarization of Biexciton Emission in Monolayer WS2
• Singlet and triplet trions in WS${}_2$ monolayer encapsulated in hexagonal boron nitride
• Strain-controlled spin splitting in the conduction band of monolayer WS2
• Theory of intervalley Coulomb interactions in monolayer transition-metal dichalcogenides
• Disentangling the effects of doping, strain and defects in monolayer WS2 by optical spectroscopy
• Two-dimensional double-quantum spectroscopy: peak shapes as a sensitive probe of carrier interactions in quantum wells
• Isolating quantum coherence with pathway-selective coherent multi-dimensional spectroscopy
• Separating Pathways in Double-Quantum Optical Spectroscopy Reveals Excitonic Interactions

Cited by in corpus (5)

• Roadmap for Photonics with 2D Materials
• Exciton-polaron interactions in monolayer WS${}_2$
• Effects of Floquet Engineering on the Coherent Exciton Dynamics in Monolayer WS${}_2$
• Efficient calculation of trion energies in monolayer transition metal dichalcogenides
• Variational and field-theoretical approach to exciton-exciton interactions and biexcitons in semiconductors