Weakly Trapped, Charged, and Free Excitons in Single-Layer MoS2 in the Presence of Defects, Strain, and Charged Impurities
arXiv:1805.02374 · doi:10.1021/acsnano.7b05520
Abstract
Few- and single-layer MoS2 host substantial densities of defects. They are thought to influence the doping level, the crystal structure, and the binding of electron-hole pairs. We disentangle the concomitant spectroscopic expression of all three effects and identify to what extent they are intrinsic to the material or extrinsic to it, i.e., related to its local environment. We do so by using different sources of MoS2 -- a natural one and one prepared at high pressure and high temperature -- and different substrates bringing varying amounts of charged impurities and by separating the contributions of internal strain and doping in Raman spectra. Photoluminescence unveils various optically active excitonic complexes. We discover a defect-bound state having a low binding energy of 20 meV that does not appear sensitive to strain and doping, unlike charged excitons. Conversely, the defect does not significantly dope or strain MoS2. Scanning tunneling microscopy and density functional theory simulations point to substitutional atoms, presumably individual nitrogen atoms at the sulfur site. Our work shows the way to a systematic understanding of the effect of external and internal fields on the optical properties of two-dimensional materials.
References in corpus (33)
- Atomically thin MoS2: A new direct-gap semiconductor
- Two Dimensional Atomic Crystals
- Observation of tightly bound trions in monolayer MoS2
- Bandgap Engineering of Strained Monolayer and Bilayer MoS2
- Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
- Observation of Long-Lived Interlayer Excitons in Monolayer MoSe2-WSe2 Heterostructures
- Tunable Photoluminescence of Monolayer MoS2 via Chemical Doping
- Local strain engineering in atomically thin MoS2
- First-principles study of the phonon-limited mobility in n-type single-layer MoS2
- Strong Photoluminescence Enhancement of MoS2 through Defect Engineering and Oxygen Bonding
- Hopping Transport through Defect-induced Localized States in Molybdenum Disulfide
- Symmetry-dependent phonon renormalization in monolayer MoS2 transistor
- Electroluminescence in Single Layer MoS2
- High Mobility Ambipolar MoS2 Field-Effect Transistors: Substrate and Dielectric Effects
- Interlayer breathing and shear modes in few-trilayer MoS2 and WSe2
- Ab-initio study on the possible doping strategies for MoS monolayers
- Electronic Properties of Graphene Encapsulated with Different Two-Dimensional Atomic Crystals
- Visibility of dichalcogenide nanolayers
- Band-Like Transport in High Mobility Unencapsulated Single-Layer MoS2 Transistors
- Thickness-Dependent Interfacial Coulomb Scattering in Atomically Thin Field-Effect Transistors
- Bandgap and doping effects in MoS2 measured by Scanning Tunneling Microscopy and Spectroscopy
- Optical identification of atomically thin dichalcogenide crystals
- Electron states of mono- and bilayer graphene on SiC probed by STM
- Many-Body Theory of Trion Absorption Features in Two-Dimensional Semiconductors
- A new multi-center approach to the exchange-correlation interactions in ab initio tight-binding methods
- Optical detection of strain and doping inhomogenieties in single layer MoS2
- Surface Recombination Limited Lifetimes of Photoexcited Carriers in Few-Layer Transition Metal Dichalcogenide MoS2
- Raman spectroscopy of the interlayer shear mode in few-layer MoS2 flakes
- Optical investigation of the natural electron doping in thin MoS2 films deposited on dielectric substrates
- Coherent Electronic Coupling in Atomically Thin MoSe2
- Many-body and spin-orbit effects on direct-indirect band gap transition of strained monolayer MoS and WS
- MoS2: a Choice Substrate for Accessing and Tuning the Electronic Properties of Graphene
- Direct observation of internal quantum transitions and femtosecond radiative decay of excitons in monolayer WSe_2
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- Dimensional crossover of acoustic phonon lifetime in -MoSe
- Anharmonicity in Raman-active phonon modes in atomically thin MoS
- Disentangling the effects of doping, strain and defects in monolayer WS2 by optical spectroscopy
- Band Bending and Valence Band Quantization at Line Defects in MoS
- Apparent Differences between Single Layer Molybdenum Disulfide Fabricated via Chemical Vapor Deposition and Exfoliation
- Interlayer Charge Transfer and Defect Creation in Type I van der Waals Heterostructures
- Probing defect states in few-layer MoS by conductance fluctuation spectroscopy
- Intrinsic edge excitons in two-dimensional MoS
- Coherence and density dynamics of excitons in a single-layer MoS reaching the homogeneous limit