Ultrafast Dynamics of Defect-Assisted Electron–Hole Recombination in Monolayer MoS 2

In this Letter, we present nondegenerate ultrafast optical pump-probe studies of the carrier recombination dynamics in MoS2 monolayers. By tuning the probe to wavelengths much longer than the exciton line, we make the probe transmission sensitive to the total population of photoexcited electrons and holes. Our measurement reveals two distinct time scales over which the photoexcited electrons and holes recombine; a fast time scale that lasts ∼ 2 ps and a slow time scale that lasts longer than ∼ 100 ps. The temperature and the pump fluence dependence of the observed carrier dynamics are consistent with defect-assisted recombination as being the dominant mechanism for electron-hole recombination in which the…

• NS
  National Science Foundation
• CC
  Cornell Center for Materials Research
• MU
  Multidisciplinary University Research Initiative
• OO
  Office of Naval Research

  Award: N00014-12-1-0072
• DO
  Division of Materials Research

  Award: DMR-1120296
• AF
  Air Force Office of Scientific Research

  Award: FA9550-09-1-0705