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

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  • Paulina Majchrzak
  • Klara Volckaert
  • Antonija Grubišić Čabo, Royal Institute of Technology
  • ,
  • Deepnarayan Biswas
  • Marco Bianchi
  • Sanjoy K. Mahatha, Ruprecht Haensel Laboratory, German Electron Synchrotron
  • ,
  • Maciej Dendzik, Department of Applied Physics, Royal Institute of Technology
  • ,
  • Federico Andreatta
  • ,
  • Signe S. Grønborg
  • ,
  • Igor Marković, University of St Andrews, Max Planck Institute for Chemical Physics of Solids
  • ,
  • Jonathon M. Riley, University of St Andrews
  • ,
  • Jens C. Johannsen
  • Daniel Lizzit, University of Udine
  • ,
  • Luca Bignardi, University of Trieste
  • ,
  • Silvano Lizzit, Sincrotrone Trieste
  • ,
  • Cephise Cacho, Diamond Light Source
  • ,
  • Oliver Alexander, Rutherford Appleton Laboratory
  • ,
  • Dan Matselyukh, Rutherford Appleton Laboratory
  • ,
  • Adam S. Wyatt, Rutherford Appleton Laboratory
  • ,
  • Richard T. Chapman, Rutherford Appleton Laboratory
  • ,
  • Emma Springate, Rutherford Appleton Laboratory
  • ,
  • Jeppe V. Lauritsen
  • Phil D.C. King, University of St Andrews
  • ,
  • Charlotte E. Sanders
  • ,
  • Jill A. Miwa
  • Philip Hofmann
  • Søren Ulstrup

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 MoS2. These timescales are explained by Auger recombination involving MoS2 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.

Original languageEnglish
Article number147093
JournalJournal of Electron Spectroscopy and Related Phenomena
Volume250
ISSN0368-2048
DOIs
Publication statusPublished - Jul 2021

Bibliographical note

Publisher Copyright:
© 2021 The Author(s)

    Research areas

  • Bandgap renormalization, Time-and angle-resolved photoemission spectroscopy, Transition metal dichalcogenides, Ultrafast carrier dynamics

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