Strain-induced structural phase transformation in two-dimensional molydenum tungsten diselenide alloy

ORAL

Abstract

Two-dimensional transition metal dichalcogenides (TMDCs) show intriguing mechanical properties compared to their bulk counterparts. This behavior can be modified in alloyed TMDCs due to doping and defects. In this work we develop CVD synthesis of large-area monolayer MoWSe2 alloy film on sapphire substrate. With Raman spectroscopy and mapping, we investigate the microscopic behavior of this alloy film transferred onto a flexible substrate as function of increasing bending strain. We observe the nature of crack propagation through the Mo and W-dominated regions in this 2D alloy film with differing stress concentration near the W-rich precipitates. Our molecular dynamics simulations illustrate how stress buildup at propagating crack tip in the film result in a 2H-1T phase transformation which is verified at micro- and nano-scale using Raman mapping and HAADF-STEM imaging. The MD simulations also predict increased crack resistance and healing in alloys compared to unalloyed pristine samples.

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Presenters

  • Amey Anant Apte

    Materials Science & NanoEngineering, Rice University

Authors

  • Amey Anant Apte

    Materials Science & NanoEngineering, Rice University

  • Vidya Kochat

    Materials Science & NanoEngineering, Rice University

  • Pankaj Rajak

    University of Southern California, Argonne national laboratory, Argonne Leadership Computing Facility, Argonne National Laboratory, Physics & Astronomy, University of Southern California

  • Aravind Krishnamoorthy

    University of Southern California, Physics & Astronomy, University of Southern California

  • Praveena Manimunda

    Bruker Nano Surfaces

  • Jordan Hachtel

    Center for Nanophase Materials Science, Oak Ridge National Laboratory

  • Juan Idrobo

    Center for Nanophase Materials Science, Oak Ridge National Laboratory

  • Syed Asif Amanulla

    Bruker Nano Surfaces

  • Priya Vashishta

    University of Southern California, Physics, University of Southern California, Collaboratory for Advanced Computing and Simulations, University of Southern California, Physics & Astronomy, University of Southern California

  • Aiichiro Nakano

    University of Southern California, Physics, University of Southern California, Physics & Astronomy, University of Southern California

  • Rajiv Kalia

    University of Southern California, Physics, University of Southern California, Physics & Astronomy, University of Southern California

  • Chandra Sekhar Tiwary

    Materials Science & NanoEngineering, Rice University

  • Pulickel M Ajayan

    Department of Materials Science and Nano Engineering, Rice University, Houston, TX, USA, Department of Materials Science and Nano Engineering, Rice University, Houston, TX-77005, USA., Rice University, Materials Science & NanoEngineering, Rice University, Department of Materials Science and Nano Engineering, Rice University