Hundredfold Enhancement of Light Emission via Defect Control in Monolayer Transition-Metal Dichalcogenides

Abstract

Two dimensional (2D) transition-metal dichalcogenide (TMD) based semiconductors have generated intense recent interest due to their novel optical and electronic properties, and potential for applications. In this work, we characterize the atomic and electronic nature of intrinsic point defects found in single crystals of these materials synthesized by two different methods - chemical vapor transport and self-flux growth. Using a combination of scanning tunneling microscopy (STM) and scanning transmission electron microscopy (STEM), we show that the two major intrinsic defects in these materials are metal vacancies and chalcogen antisites. We show that by control of the synthetic conditions, we can reduce the defect concentration from above $10^{13}/c{m}^2$ to below $10^{11}/c{m}^2$. Because these point defects act as centers for non-radiative recombination of excitons, this improvement in material quality leads to a hundred-fold increase in the radiative recombination efficiency.

References in corpus (25)

• Boron nitride substrates for high-quality graphene electronics
• Synthesis of Large-Area MoS2 Atomic Layers with Chemical Vapor Deposition
• Type-II Weyl Semimetals
• Grains and grain boundaries in highly crystalline monolayer molybdenum disulfide
• Micrometer-scale ballistic transport in encapsulated graphene at room temperature
• Direct observation of the transition from indirect to direct bandgap in atomically thin epitaxial MoSe2
• Atomically thin boron nitride: a tunnelling barrier for graphene devices
• Electrical Transport Properties of Single-Layer WS2
• Ultrafast Dynamics of Defect-Assisted Electron-Hole Recombination in Monolayer MoS2
• High-temperature superfluidity with indirect excitons in van der Waals heterostructures
• Electrical control of the valley Hall effect in bilayer MoS2 transistors
• Intrinsic Transport Properties of Electrons and Holes in Monolayer Transition Metal Dichalcogenides
• Bandgap and doping effects in MoS2 measured by Scanning Tunneling Microscopy and Spectroscopy
• A systematic study of structural, electronic and optical properties of atomic scale defects in 2D transition metal dichalcogenides MX${}_2$ (M = Mo,W; X = S, Se, Te)
• Exciton Dynamics in Monolayer Transition Metal Dichalcogenides
• Observation of Large Topologically Trivial Fermi-Arcs in the Candidate Type-II Weyl Semimetal WTe2
• Intervalley biexcitons and many-body effects in monolayer MoS2
• Exciton and trion dynamics in atomically thin MoSe2 and WSe2: effect of localization
• Polarization analysis of excitons in monolayer and bilayer transition-metal dichalcogenides
• Magneto-optics in transition metal diselenide monolayers
• Fast Exciton Annihilation by Capture of Electrons or Holes by Defects via Auger Scattering in Monolayer Metal Dichalcogenides
• Dark excitons and the elusive valley polarization in transition metal dichalcogenides
• Local Spectroscopic Characterization of Spin and Layer Polarization in WSe${}_2$
• Interband Tunneling in 2D Crystal Semiconductors
• Observation of bright and dark exciton transitions in monolayer MoSe2 by photocurrent spectroscopy

Cited by in corpus (51)

• Magic continuum in twisted bilayer WSe2
• Interfacial ferroelectricity in rhombohedral-stacked bilayer transition metal dichalcogenides
• One-Dimensional Moiré Excitons in Transition-Metal Dichalcogenide Heterobilayers
• Imaging strain-localized exciton states in nanoscale bubbles in monolayer WSe2 at room temperature
• Deep moiré potentials in twisted transition metal dichalcogenide bilayers
• Localized inter-valley defect excitons as single-photon emitters in WSe${}_2$
• Accessing high optical quality of MoS2 monolayers grown by chemical vapor deposition
• Oxidation of Monolayer WS${}_2$ in Ambient is a Photoinduced Process
• Epitaxial Growth of 2D Layered Transition Metal Dichalcogenides
• Moiré metrology of energy landscapes in van der Waals heterostructures
• Nano-imaging of intersubband transitions in van der Waals quantum wells
• Odd- and even-denominator fractional quantum Hall states in monolayer WSe${}_2$
• Band gap measurements of monolayer h-BN and insights into carbon-related point defects
• Tunable strain soliton networks confine electrons in Van der Waals materials
• Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2 Heterobilayers
• Antisite defect qubits in monolayer transition metal dichalcogenides
• Imaging non-radiative point defects buried in quantum wells using cathodoluminescence
• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
• Valley relaxation of resident electrons and holes in a monolayer semiconductor: Dependence on carrier density and the role of substrate-induced disorder
• Localized Excitons in NbSe${}_2$-MoSe${}_2$ Heterostructures
• Localization and interaction of interlayer excitons in MoSe${}_2$/WSe${}_2$ heterobilayers
• Evidence for Exciton Crystals in a 2D Semiconductor Heterotrilayer
• Dark-exciton driven energy funneling into dielectric inhomogeneities in two-dimensional semiconductors
• Tunneling-current-induced local excitonic luminescence in p-doped WSe${}_2$ monolayers
• Ab initio Ultrafast Spin Dynamics in Solids
• Brightening of a dark monolayer semiconductor via strong light-matter coupling in a cavity
• Optical and dielectric properties of MoO${}_3$ nanosheets for van der Waals heterostructures
• Visualizing the microscopic origins of topology in twisted molybdenum ditelluride
• Monolayer WS${}_2$ electro- and photo-luminescence enhancement by TFSI treatment
• Atomistic $T$-matrix theory of disordered 2D materials: Bound states, spectral properties, quasiparticle scattering, and transport
• Electronic transport, metal-insulator transition, and Wigner crystallization in transition metal dichalcogenide monolayers
• Multi-scale photonic emissivity engineering for relativistic lightsail thermal regulation
• Optical detection of long electron spin transport lengths in a monolayer semiconductor
• Vacancy localization effects on MX2 transition metal dichalcogenides: a systematic ab-initio study
• Abnormal behavior of preferred formation of cationic vacancy from the interior in γ-GeSe monolayer with the stereo-chemical antibonding lone-pair state
• Criteria for deterministic single-photon emission in two-dimensional atomic crystals
• Structural Modulation and Enhanced Magnetic Ordering in Incommensurate K${}_{1-x}$CrSe${}_2$ Crystals
• Imaging the Sub-Moiré Potential Landscape using an Atomic Single Electron Transistor
• Optically Facet-Resolved Reaction Anisotropy in Two-Dimensional Transition Metal Dichalcogenides
• Second-harmonic imaging microscopy for time-resolved investigations of transition metal dichalcogenides
• Hydrogenic Spin-Valley states of the Bromine donor in 2H-MoTe${}_2$
• Single photon emitters with polarization and orbital angular momentum locking in monolayer semiconductors
• Transport anomalies in the layered compound BaPt4Se6
• Polarized and narrow excitonic emission from graphene-capped monolayer WS${}_2$ through resonant phonon relaxation
• Disorder of Excitons and Trions in Monolayer MoSe2
• Cryogenic Nano-Imaging of Excitons in a Monolayer Semiconductor
• Single photon emission in $WS{e}_2$ up 160 K by quantum yield control
• Substrate dopant induced electronic inhomogeneity in epitaxial bilayer graphene
• Shedding light on the monolayer-WSe2 exciton's nature by optical effective-mass measurements
• Epitaxy of new layered materials: 2D chalcogenides and challenges of weak van der Waals interactions
• Spatially Resolved Persistent Photoconductivity in MoS${}_2$-WS${}_2$ Lateral Heterostructures