Observation of Ultrafast Free Carrier Dynamics in Single Layer MoS${}_2$

Abstract

The dynamics of excited electrons and holes in single layer (SL) MoS${}_2$ have so far been difficult to disentangle from the excitons that dominate the optical response of this material. Here, we use time- and angle-resolved photoemission spectroscopy for a SL of MoS${}_2$ on a metallic substrate to directly measure the excited free carriers. This allows us to ascertain a direct quasiparticle band gap of 1.95 eV and determine an ultrafast (50 fs) extraction of excited free carriers via the metal in contact with the SL MoS${}_2$. This process is of key importance for optoelectronic applications that rely on separated free carriers rather than excitons.

15 pages, 4 Figures. To appear in Nano Letters, 2015

References in corpus (7)

• Valley polarization in MoS2 monolayers by optical pumping
• Ultrafast Charge Transfer in Atomically Thin MoS2/WS2 Heterostructures
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Ultrafast Dynamics of Defect-Assisted Electron-Hole Recombination in Monolayer MoS2
• Ultrafast and spatially resolved studies of charge carriers in atomically-thin molybdenum disulfide
• Electronic Structure of Epitaxial Single-Layer MoS${}_2$
• Synthesis of Epitaxial Single-Layer MoS${}_2$ on Au(111)

Cited by in corpus (57)

• Directly visualizing the momentum forbidden dark excitons and their dynamics in atomically thin semiconductors
• Generation and evolution of spin-, valley- and layer-polarized excited carriers in inversion-symmetric WSe2
• Single-layer MoS${}_2$ on Au(111): band gap renormalization and substrate interaction
• Direct Determination of Band Gap Renormalization in Photo-Excited Monolayer MoS2
• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Light matter interaction in transition metal dichalcogenides and their heterostructures
• Ultrafast Band Structure Control of a Two-Dimensional Heterostructure
• Crystalline and electronic structure of single-layer TaS${}_2$
• Ultrafast Angle-Resolved Photoemission Spectroscopy of Quantum Materials
• Electronic band structure of Two-Dimensional WS2/Graphene van der Waals Heterostructures
• Intervalley scattering in MoS${}_2$ imaged by two-photon photoemission with a high-harmonic probe
• Photoemission signature of excitons
• Nonequilibrium Lattice Dynamics in Monolayer MoS2
• Moiré structure of MoS${}_2$ on Au(111): Local structural and electronic properties
• A setup for extreme-ultraviolet ultrafast angle-resolved photoelectron spectroscopy at 50-kHz repetition rate
• Direct determination of momentum resolved electron transfer in the photo-excited MoS2/WS2 van der Waals heterobilayer by TR-ARPES
• A quantitative comparison of time-of-flight momentum microscopes and hemispherical analyzers for time- and angle-resolved photoemission spectroscopy experiments
• Spin and Valley Control of Free Carriers in Single-Layer WS${}_2$
• Spatially Resolved Electronic Properties of Single-Layer WS${}_2$ on Transition Metal Oxides
• Excitation-induced transition to indirect band gaps in atomically thin transition metal dichalcogenide semiconductors
• Unveiling Defect-Mediated Carrier Dynamics in Monolayer Semiconductors by Spatiotemporal Microwave Imaging
• Contact-Induced Semiconductor-to-Metal Transition in Single-Layer WS${}_2$
• Momentum-Resolved Exciton Coupling and Valley Polarization Dynamics in Monolayer WS${}_2$
• Spin structure of K valleys in single-layer WS${}_2$ on Au(111)
• Nanoscale patterning of quasiparticle band alignment
• Larger than 80% Valley Polarization of Free Carriers in Singly-Oriented Single Layer WS${}_2$ on Au(111)
• Ultrafast dynamics of bright and dark excitons in monolayer WSe${}_2$ and heterobilayer WSe${}_2$/MoS${}_2$
• Harnessing Exciton-Exciton Annihilation in Two-Dimensional Semiconductors
• Epitaxial single layer NbS${}_2$ on Au(111): synthesis, structure, and electronic properties
• Exciton-Driven Renormalization of Quasiparticle Band Structure in Monolayer MoS2
• Electron-phonon coupling in the spin-split valence band of single layer WS${}_2$
• Accessing the spectral function of in operando devices by angle-resolved photoemission spectroscopy
• Hot carrier extraction from 2D semiconductor photoelectrodes
• Ultrafast spin density wave transition in Chromium governed by thermalized electron gas
• Advancing time- and angle-resolved photoemission spectroscopy: The role of ultrafast laser development
• Comprehensive tunneling spectroscopy of quasi-freestanding MoS${}_2$ on graphene on Ir(111)
• Generalized scaling law for exciton binding energy in two-dimensional materials
• Moiré tuning of spin excitations: Individual Fe atoms on MoS${}_2$/Au(111)
• Ultrafast electrons dynamics reveal the high potential of InSe for hot carrier optoelectronics
• Charge transfer-induced Lifshitz transition and magnetic symmetry breaking in ultrathin CrSBr crystals
• Layer and orbital interference effects in photoemission from transition metal dichalcogenides
• Towards full surface Brillouin zone mapping by coherent multi-photon photoemission
• Revealing Ultrafast Phonon Mediated Inter-Valley Scattering through Transient Absorption and High Harmonic Spectroscopies
• Momentum-resolved linear dichroism in bilayer MoS${}_2$
• Nonequilibrium Electron Dynamics In Pump-Probe Spectroscopy: Role Of Excited Phonon Populations
• Thermalization of photoexcited carriers in two-dimensional transition metal dichalcogenides and internal quantum efficiency of van der Waals heterostructures
• Probing excitons with time-resolved momentum microscopy
• Isolating the Nonlinear Optical Response of a MoS${}_2$ Monolayer under Extreme Screening of a Metal Substrate
• Review: Advanced characterization of the spatial variation of moiré heterostructures and moiré excitons
• Ultrafast Carrier Dynamics in Two-Dimensional Electron Gas-Like K-doped MoS2
• Bulk band structure of Sb${}_2$Te${}_3$ determined by angle-resolved photoemission spectroscopy
• Moiré induced electronic structure modifications in monolayer V${}_2$S${}_3$ on Au(111)
• Quasiparticle gap renormalization driven by internal and external screening in a WS${}_2$ device
• Symmetry-breaking and spin-blockage effects on carrier dynamics in single-layer tungsten diselenide
• Light-matter interactions in layered materials and heterostructures: from moiré physics and magneto-optical effects to ultrafast dynamics and hybrid meta-photonics
• Phonon-assisted carrier cooling in h-BN/graphene van der Waals heterostructures
• Ultrafast Charge Transfer Dynamics at the MoS${}_2$/Au Interface Observed via Optical Spectroscopy under Ambient Conditions