Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016)
    Thin Films Tuesday Sessions
       Session TF-TuE

Paper TF-TuE5
Probing Atomic Structure of 2D TMDs by High Resolution STEM

Tuesday, December 13, 2016, 7:00 pm, Room Makai

Session: Growth & Characterization of 2D Materials
Presenter: Moon Kim, The University of Texas at Dallas, USA
Authors: M. Kim, The University of Texas at Dallas, USA
Q. Wang, The University of Texas at Dallas, USA
J. Wang, The University of Texas at Dallas, USA
Correspondent: Click to Email
As the scaling of various functional devices continues, the future of these devices will rely on new class of materials. Research in graphene and the methodology of preparing ultrathin layers has led to the exploration of other 2D materials. In particular, single layers of transition metal dichalcogenides (TMDs) with lamellar structures similar to those of graphite have drawn significant attention because of their tunable bandgaps. TMDs exhibit diverse properties that depend on their composition: semiconductors, semimetals, metals, or superconductors. TMD properties also strongly depend on the crystalline structure, including the number and stacking sequence of layers. In exploring and developing these emerging materials, nanoscale characterization becomes ever more important. In particular, high resolution electron microscopy-based techniques now are capable of analyzing these 2D nano-materials and devices with better than 0.1 nm resolution. Here, we present our recent studies on the characterization of 2D layered materials by means of Scanning Transmission Electron Microscopy (STEM), specifically High Angle Annular Dark Field (HAADF) imaging and in-situ Transmission Electron Microscopy (TEM). We have identified the atomic arrangements and defects in single layer MoS2, 2H stacked TMDs, 1T stacked TMDs, and distorted 1T stacked TMDs by HAADF STEM imaging . The location and nature of individual atoms, defects, phase transformation, and layer by layer shearing of 2D crystals will be presented and discussed in detail.