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Structural and Optical Stability of Bilayer and Few-Layer MoS$_{\mathrm{2}}$ in Ambient Air.

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Abstract

We investigate the stability of MoS$_{\mathrm{2}}$ in ambient air, with a focus on monolayers, bilayers, twisted bilayers with large twist angles, and few-layers. The samples are grown using chemical vapor deposition on SiO$_{\mathrm{2}}$ substrates and studied atomic force microscopy (AFM), and Raman and photoluminescence spectroscopy. We find that as-grown bilayers with twist angles of 0$^{\mathrm{o}}$ and 60$^{\mathrm{o}}$ are remarkably structurally stable in comparison to monolayers that significantly structurally degrade in ambient air. Bilayers with 0$^{\mathrm{o}}$ twist angles synthesized using transfer of monolayers on top of one another are also found to be stable. Few-layers with twist angles of 0$^{\mathrm{o}}$ with number of layers n $=$ 3-6 are also stable. However, we find that transferred twisted bilayers with twist angles of about 10$^{\mathrm{o}}$ are significantly unstable in ambient air. Possible explanations for these observations will be discussed.

Authors

  • John Femi-Oyetoro

    University of North Texas

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi

  • Mohammad Barzegar

    Vanderbilt University, Rowan University, California State University (retired), University of North Texas, Michigan Technological University, Texas A&M University, University of Texas at El Paso, Cornell University, Rice University, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, 2020 National PhysTEC Teacher of the Year, Fresno State Physics Department, University of Texas at Arlington, Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A & M University, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, University of Miami, Texas A&M University–Corpus Christi