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Title: Raman shifts in electron-irradiated monolayer MoS 2

Here, we report how the presence of electron-beam-induced sulfur vacancies affects first-order Raman modes and correlate the effects with the evolution of the in situ transmission-electron microscopy (TEM) two-terminal conductivity of monolayer MoS 2 under electron irradiation. We observe a redshift in the E Raman peak and a less pronounced blueshift in the A' 1 peak with increasing electron dose. Using energy-dispersive X-ray spectroscopy (EDS), we show that irradiation causes partial removal of sulfur and correlate the dependence of the Raman peak shifts with S vacancy density (a few %), which is confirmed by first-principles density functional theory calculations. In situ device current measurements show exponential decrease in channel current upon irradiation. Our analysis demonstrates that the observed frequency shifts are intrinsic properties of the defective systems and that Raman spectroscopy can be used as a quantitative diagnostic tool to characterize MoS 2-based transport channels.
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1] ;  [3] ;  [1]
  1. Univ. of Pennsylvania, Philadelphia, PA (United States)
  2. Rensselaer Polytechnic Inst., Troy, NY (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Rensselaer Polytechnic Inst., Troy, NY (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 10; Journal Issue: 4; Journal ID: ISSN 1936-0851
American Chemical Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
77 NANOSCIENCE AND NANOTECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; MoS2; two-dimensional material; Raman; in situ transmission electron microscopy; transition-metal dichalcogenide
OSTI Identifier: