Recoil Effect and Photoemission Splitting of Trions in Monolayer MoS2

Qicheng Zhang, Carl H. Naylor, Zhaoli Gao, Ruizhe Wu, Irfan Haider Abidi, Meng Qiang Zhao, Yao Ding, Aldrine Abenoja Cagang, Minghao Zhuang, Xuewu Ou, Zhengtang Luo

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The 2D geometry nature and low dielectric constant in transition-metal dichalcogenides lead to easily formed strongly bound excitons and trions. Here, we studied the photoluminescence of van der Waals heterostructures of monolayer MoS2 and graphene at room temperature and observed two photoluminescence peaks that are associated with trion emission. Further study of different heterostructure configurations confirms that these two peaks are intrinsic to MoS2 and originate from a bound state and Fermi level, respectively, of which both accept recoiled electrons from trion recombination. We demonstrate that the recoil effect allows us to electrically control the photon energy of trion emission by adjusting the gate voltage. In addition, significant thermal smearing at room temperature results in capture of recoil electrons by bound states, creating photoemission peak at low doping level whose photon energy is less sensitive to gate voltage tuning. This discovery reveals an unexpected role of bound states for photoemission, where binding of recoil electrons becomes important.

Original languageEnglish (US)
Pages (from-to)10808-10815
Number of pages8
JournalACS Nano
Issue number11
StatePublished - Nov 28 2017
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


  • 2D materials
  • doping
  • molybdenum disulfide
  • photoluminescence
  • trion


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