Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Samuel Brem - , Chalmers University of Technology (Author)
  • Jonas Zipfel - , University of Regensburg (Author)
  • Malte Selig - , Technical University of Berlin (Author)
  • Archana Raja - , University of California at Berkeley (Author)
  • Lutz Waldecker - , Stanford University (Author)
  • Jonas D. Ziegler - , University of Regensburg (Author)
  • Takashi Taniguchi - , National Institute for Materials Science Tsukuba (Author)
  • Kenji Watanabe - , National Institute for Materials Science Tsukuba (Author)
  • Alexey Chernikov - , University of Regensburg (Author)
  • Ermin Malic - , Chalmers University of Technology (Author)

Abstract

The reduced dielectric screening in atomically thin transition metal dichalcogenides allows to study the hydrogen-like series of higher exciton states in optical spectra even at room temperature. The width of excitonic peaks provides information about the radiative decay and phonon-assisted scattering channels limiting the lifetime of these quasi-particles. While linewidth studies so far have been limited to the exciton ground state, encapsulation with hBN has recently enabled quantitative measurements of the broadening of excited exciton resonances. Here, we present a joint experiment-theory study combining microscopic calculations with spectroscopic measurements on the intrinsic linewidth and lifetime of higher exciton states in hBN-encapsulated WSe2 monolayers. Surprisingly, despite the increased number of scattering channels, we find both in theory and experiment that the linewidth of higher excitonic states is similar or even smaller compared to the ground state. Our microscopic calculations ascribe this behavior to a reduced exciton-phonon scattering efficiency for higher excitons due to spatially extended orbital functions.

Details

Original languageEnglish
Pages (from-to)12381-12387
Number of pages7
JournalNanoscale
Volume11
Issue number25
Publication statusPublished - 7 Jul 2019
Peer-reviewedYes
Externally publishedYes

External IDs

PubMed 31215947

Keywords

ASJC Scopus subject areas