Oxygen passivation mediated tunability of trion and excitons in MoS${}_2$

Abstract

Using wide spectral range in situ spectroscopic ellipsometry with systematic ultra high vacuum annealing and in situ exposure to oxygen, we report the complex dielectric function of MoS${}_2$ isolating the environmental effects and revealing the crucial role of unpassivated and passivated sulphur vacancies. The spectral weights of the A ($1.92$ eV) and B ($2.02$ eV) exciton peaks in the dielectric function reduce significantly upon annealing, accompanied by spectral weight transfer in a broad energy range. Interestingly, the original spectral weights are recovered upon controlled oxygen exposure. This tunability of the excitonic effects is likely due to passivation and reemergence of the gap states in the bandstructure during oxygen adsorption and desorption, respectively, as indicated by ab initio density functional theory calculation results. This work unravels and emphasizes the important role of adsorbed oxygen in the optical spectra and many-body interactions of MoS${}_2$.

arXiv commentAccepted in Physical Review Letters; Main Article: 6 pages, 4 figures; Supplemental Material: 6 pages, 7 figures, 10 tables

References in corpus (18)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Observation of tightly bound trions in monolayer MoS2
• Optical Spectrum of MoS${}_2$: Many-body Effects and Diversity of Exciton States
• Electrical Control of Two-Dimensional Neutral and Charged Excitons in a Monolayer Semiconductor
• Tunable Photoluminescence of Monolayer MoS2 via Chemical Doping
• Measurement of the optical dielectric function of transition metal dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2
• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Strong Photoluminescence Enhancement of MoS2 through Defect Engineering and Oxygen Bonding
• Theory of Neutral and Charged Excitons in Monolayer Transition Metal Dichalcogenides
• Intrinsic Exciton Linewidth in Monolayer Transition Metal Dichalcogenides
• Controlling many-body states by the electric-field effect in a two-dimensional material
• Absorption of Light by Excitons and Trions in Monolayers of Metal Dichalcogenide MoS${}_2$: Experiments and Theory
• Electrical Control of Optical Properties of Monolayer MoS${}_2$
• Coupling of excitons and defect states in boron-nitride nanostructures
• Exciton dynamics in atomically thin MoS2: inter-excitonic interaction and broadening kinetics
• Intervalley biexcitons and many-body effects in monolayer MoS2
• Broad Band Optical Properties of Large Area Monolayer CVD Molybdenum Disulfide
• Air passivation of chalcogen vacancies in two-dimensional semiconductors

Cited by in corpus (10)

• Controllable Water Vapor Assisted Chemical Vapor Transport Synthesis of WS2-MoS2 Heterostructure
• Gate-tunable emission of exciton-plasmon polaritons in hybrid MoS2-gap-mode metasurfaces
• Defect Passivation of 2D Semiconductors by Fixating Chemisorbed Oxygen Molecules via h-BN Encapsulations
• Electronic Properties of Defective MoS${}_2$ Monolayers Subject to Mechanical Deformations: A First-Principles Approach
• Effect of strain and sulfur vacancies on the luminescence and valley polarization properties of CVD grown monolayer MoS${}_2$ films
• Tunability of electrical and thermoelectrical properties of monolayer MoS${}_2$ through oxygen passivation
• Intrinsic edge excitons in two-dimensional MoS${}_2$
• Effect of manganese incorporation on the excitonic recombination dynamics in monolayer MoS${}_2$
• Interfacial Polarons Driven by Charge Transfer In WSe2/Cuprate Superconductor Systems
• Momentum Conserved Ultrafast Charge Transfer Dynamics of Interlayer Excitons in vdW Heterostructures