Mesoscale imperfections in MoS2 atomic layers grown by a vapor transport technique

Yingnan Liu, Rudresh Ghosh, Di Wu, Ariel Ismach, Rodney Ruoff, Keji Lai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The success of isolating small flakes of atomically thin layers through mechanical exfoliation has triggered enormous research interest in graphene and other two-dimensional materials. For device applications, however, controlled large-area synthesis of highly crystalline monolayers with a low density of electronically active defects is imperative. Here, we demonstrate the electrical imaging of dendritic ad-layers and grain boundaries in monolayer molybdenum disulfide (MoS2) grown by a vapor transport technique using microwave impedance microscopy. The micrometer-sized precipitates in our films, which appear as a second layer of MoS2 in conventional height and optical measurements, show ∼2 orders of magnitude higher conductivity than that of the single layer. The zigzag grain boundaries, on the other hand, are shown to be more resistive than the crystalline grains, consistent with previous studies. Our ability to map the local electrical properties in a rapid and nondestructive manner is highly desirable for optimizing the growth process of large-scale MoS2 atomic layers.

Original languageEnglish
Pages (from-to)4682-4686
Number of pages5
JournalNano Letters
Volume14
Issue number8
DOIs
StatePublished - 13 Aug 2014
Externally publishedYes

Keywords

  • 2D materials
  • Molybdenum disulfide
  • atomic layers
  • grain boundary
  • mesoscopic defects
  • microwave impedance microscopy

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