Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides

Abstract Atomically thin transition metal dichalcogenides are direct-gap semiconductors with strong light–matter and Coulomb interactions. The latter accounts for tightly bound excitons, which dominate their optical properties. Besides the optically accessible bright excitons, these systems exhibit a variety of dark excitonic states. They are not visible in the optical spectra, but can strongly influence the coherence lifetime and the linewidth of the emission from bright exciton states. Here, we investigate the microscopic origin of the excitonic coherence lifetime in two representative materials (WS 2 and MoSe 2 ) through a study combining microscopic theory with spectroscopic measurements. We show that the…

• NS
  National Science Foundation

  Awards: DMR-1420634, 1420634
• UD
  U.S. Department of Energy
• WM
  W. M. Keck Foundation
• GA
  Gordon and Betty Moore Foundation

  Awards: No. GBMF4545, GBMF4545
• GF
  Graphene Flagship

  Awards: CNECT-ICT-604391, 604391
• DF
  Deutsche Forschungsgemeinschaft

  Award: SFB 689
• OO
  Office of Science
• MR
  Materials Research Science and Engineering Center, Harvard University

  Awards: 1420634, DMR-1420634
• DO
  Division of Materials Research

  Awards: DMR-1420634, 1420634
• BE
  Basic Energy Sciences
• CS
  Chemical Sciences, Geosciences, and Biosciences Division
• SN
  SLAC National Accelerator Laboratory