DOI

  • N. Lundt
  • E. Cherotchenko
  • O. Iff
  • X. Fan
  • Y. Shen
  • P. Bigenwald
  • A. V. Kavokin
  • S. Höfling
  • C. Schneider

The luminescence and absorption properties of transition metal dichalcogenide monolayers are widely determined by neutral and charged excitonic complexes. Here, we focus on the impact of a free carrier reservoir on the optical properties of excitonic and trionic complexes in a MoSe2 monolayer at cryogenic temperatures. By applying photodoping via a non-resonant pump laser, the electron density can be controlled in our sample, which is directly reflected in the contribution of excitons and trions to the luminescence signal. We find significant shifts of both the exciton and trion energies in the presence of an induced electron gas both in power- and in time evolution (on the second to minute scale) in our photoluminescence spectra. In particular, in the presence of the photo-doped carrier reservoir, we observe that the splitting between excitons and trions can be enhanced by up to 4 meV. This behaviour is phenomenologically explained by an interplay between an increased screening of excitons via electrons in our system and a modification of the Fermi level. We introduce a simple but still quantitative treatment of these effects within a variational approach that takes into account both screening and phase space filling effects.

Original languageEnglish
Article number031107
Number of pages5
JournalApplied Physics Letters
Volume112
Issue number3
DOIs
StatePublished - 15 Jan 2018

    Scopus subject areas

  • Physics and Astronomy (miscellaneous)

    Research areas

  • SEMICONDUCTOR QUANTUM-WELLS, TRANSITION-METAL DICHALCOGENIDES, ATOMICALLY THIN SEMICONDUCTOR, 2-DIMENSIONAL ELECTRON-GAS, CHARGED EXCITONS, WSE2, STATES, LIGHT, PHOTONICS, EMISSION

ID: 36004194