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Spectroscopic view of ultrafast charge carrier dynamics in single- and bilayer transition metal dichalcogenide semiconductors

DOI: 10.1016/j.elspec.2021.147093 DOI Help

Authors: Paulina Majchrzak (Aarhus University) , Klara Volckaert (Aarhus University) , Antonija Grubišić Čabo (KTH Royal Institute of Technology) , Deepnarayan Biswas (Aarhus University) , Marco Bianchi (Aarhus University) , Sanjoy K. Mahatha (Deutsches Elektronen-Synchrotron DESY) , Maciej Dendzik (KTH Royal Institute of Technology) , Federico Andreatta (Aarhus University) , Signe S. Grønborg (Aarhus University) , Igor Markovic (University of St Andrews; Max Planck Institute for Chemical Physics of Solids) , Jonathon M. Riley (University of St Andrews) , Jens C. Johannsen (École Polytechnique Fédérale de Lausanne (EPFL)) , Daniel Lizzit (DPIA, University of Udine) , Luca Bignardi (University of Trieste) , Silvano Lizzit (Elettra-Sincrotrone Trieste) , Cephise Cacho (Diamond Light Source) , Oliver Alexander (Central Laser Facility, STFC Rutherford Appleton Laboratory) , Dan Matselyukh (Central Laser Facility, STFC Rutherford Appleton Laboratory) , Adam S. Wyatt (Central Laser Facility, STFC Rutherford Appleton Laboratory) , Richard T. Chapman (Central Laser Facility, STFC Rutherford Appleton Laboratory) , Emma Springate (Central Laser Facility, STFC Rutherford Appleton Laboratory) , Jeppe V. Lauritsen (Aarhus University) , Phil D. C. King (University of St Andrews) , Charlotte Sanders (Aarhus University) , Jill A. Miwa (Aarhus University) , Philip Hofmann (Aarhus University) , Soeren Ulstrup (Aarhus University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Electron Spectroscopy And Related Phenomena , VOL 250

State: Published (Approved)
Published: July 2021

Open Access Open Access

Abstract: The quasiparticle spectra of atomically thin semiconducting transition metal dichalcogenides (TMDCs) and their response to an ultrafast optical excitation critically depend on interactions with the underlying substrate. Here, we present a comparative time- and angle-resolved photoemission spectroscopy (TR-ARPES) study of the transient electronic structure and ultrafast carrier dynamics in the single- and bilayer TMDCs MoS2 and WS2 on three different substrates: Au(111), Ag(111) and graphene/SiC. The photoexcited quasiparticle bandgaps are observed to vary over the range of 1.9–2.5 eV between our systems. The transient conduction band signals decay on a sub-50 fs timescale on the metals, signifying an efficient removal of photoinduced carriers into the bulk metallic states. On graphene, we instead observe a fast timescale on the order of 170 fs, followed by a slow dynamics for the conduction band decay in MoS . These timescales are explained by Auger recombination involving MoS and in-gap defect states. In bilayer TMDCs on metals we observe a complex redistribution of excited holes along the valence band that is substantially affected by interactions with the continuum of bulk metallic states.

Journal Keywords: Time-and angle-resolved photoemission spectroscopy; Transition metal dichalcogenides; Ultrafast carrier dynamics; Bandgap renormalization

Diamond Keywords: Semiconductors

Subject Areas: Materials, Physics

Technical Areas:

Added On: 23/06/2021 09:22


Discipline Tags:

Physics Hard condensed matter - structures Electronics Materials Science

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