Time-resolved ARPES Determination of a Quasi-Particle Band Gap and Hot Electron Dynamics in Monolayer MoS2

Woojoo Lee, Yi Lin, Li Syuan Lu, Wei Chen Chueh, Mengke Liu, Xiaoqin Li, Wen Hao Chang, Robert A. Kaindl, Chih Kang Shih

Research output: Contribution to journalArticlepeer-review

Abstract

The electronic structure and dynamics of 2D transition metal dichalcogenide (TMD) monolayers provide important underpinnings both for understanding the many-body physics of electronic quasi-particles and for applications in advanced optoelectronic devices. However, extensive experimental investigations of semiconducting monolayer TMDs have yielded inconsistent results for a key parameter, the quasi-particle band gap (QBG), even for measurements carried out on the same layer and substrate combination. Here, we employ sensitive time- and angle-resolved photoelectron spectroscopy (trARPES) for a high-quality large-area MoS2 monolayer to capture its momentum-resolved equilibrium and excited-state electronic structure in the weak-excitation limit. For monolayer MoS2 on graphite, we obtain QBG values of ≈2.10 eV at 80 K and of ≈2.03 eV at 300 K, results well-corroborated by the scanning tunneling spectroscopy (STS) measurements on the same material.

Original languageEnglish (US)
Pages (from-to)7363-7370
Number of pages8
JournalNano Letters
Volume21
Issue number17
DOIs
StatePublished - Sep 8 2021
Externally publishedYes

Keywords

  • electronic structure
  • exciton
  • monolayer
  • MoS
  • Transition metal dichalcogenide (TMD)
  • XUV-trARPES

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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