Free Trions with Near-Unity Quantum Yield in Monolayer MoSe2

Bumho Kim, Yue Luo, Daniel Rhodes, Yusong Bai, Jue Wang, Song Liu, Abraham Jordan, Baili Huang, Zhaochen Li, Takashi Taniguchi, Kenji Watanabe, Jonathan Owen, Stefan Strauf, Katayun Barmak, Xiaoyang Zhu, James Hone

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Trions, quasiparticles composed of an electron-hole pair bound to a second electron and/or hole, are many-body states with potential applications in optoelectronics. Trions in monolayer transition metal dichalcogenide (TMD) semiconductors have attracted recent interest due to their valley/spin polarization, strong binding energy, and tunability through external gate control. However, low materials quality (i.e., high defect density) has hindered efforts to understand the intrinsic properties of trions. The low photoluminescence (PL) quantum yield (QY) and short lifetime of trions have prevented harnessing them in device applications. Here, we study the behavior of trions in a series of MoSe2 monolayers, with atomic defect density varying by over 2 orders of magnitude. The QY increases with decreasing defect density and approaches unity in the cleanest material. Simultaneous measurement of the PL lifetime yields both the intrinsic radiative lifetime and the defect-dependent nonradiative lifetime. The long lifetime of 230 ps of trions allows direct observation of their diffusion.

Original languageEnglish
Pages (from-to)140-147
Number of pages8
JournalACS Nano
Volume16
Issue number1
DOIs
StatePublished - 25 Jan 2022

Keywords

  • MoSe
  • diffusion
  • intrinsic lifetime
  • quantum yield
  • transition metal dichalcogenide
  • trion

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