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This content will become publicly available on March 8, 2017

Title: Distinct photoluminescence and Raman spectroscopy signatures for identifying highly crystalline WS2 monolayers produced by different growth methods

We report that transition metal dichalcogenides (TMDs) such as WS2 show exciting promise in electronic and optoelectronic applications. Significant variations in the transport, Raman, and photoluminescence (PL) can be found in the literature, yet it is rarely addressed why this is. In this report, Raman and PL of monolayered WS2 produced via different methods are studied and distinct features that indicate the degree of crystallinity of the material are observed. While the intensity of the LA(M) Raman mode is found to be a useful indicator to assess the crystallinity, PL is drastically more sensitive to the quality of the material than Raman spectroscopy. We also show that even exfoliated crystals, which are usually regarded as the most pristine material, can contain large amounts of defects that would not be apparent without Raman and PL measurements. Ultimately, these findings can be applied to the understanding of other two-dimensional heterostructured systems.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1] ;  [4] ;  [1] ;  [5] ;  [3] ;  [1] ;  [6]
  1. Pennsylvania State Univ., University Park, PA (United States). Dept of Physics and Center for 2-Dimensional and Layered Materials
  2. Pennsylvania State Univ., University Park, PA (United States). Dept of Physics and Center for 2-Dimensional and Layered Materials; Erciyes Univ., Kayseri (Turkey). Nanotechnology Research Center and Kayseri Vocational College
  3. Pennsylvania State Univ., University Park, PA (United States). Dept of Chemistry
  4. Pennsylvania State Univ., University Park, PA (United States). Materials Research Inst.
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
  6. Pennsylvania State Univ., University Park, PA (United States). Dept of Physics and Center for 2-Dimensional and Layered Materials; Pennsylvania State Univ., University Park, PA (United States). Dept of Chemistry; Pennsylvania State Univ., University Park, PA (United States). Dept of Materials Science & Engineering; Shinshu Univ., Nagano (Japan)
Publication Date:
OSTI Identifier:
1311237
Grant/Contract Number:
AC05-00OR22725; W911NF-11-1-0362; DMR-0820404; EFRI-1433311
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Research
Additional Journal Information:
Journal Volume: 31; Journal Issue: 07; Journal ID: ISSN 0884-2914
Publisher:
Materials Research Society
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
U.S. Army Research Office; National Science Foundation (NSF); USDOE Office of Science (SC); Pennsylvania State Univ.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE Raman spectroscopy; luminescence; defects