Indirect bandgap measured in β'-phase In2Se3 crystals by angle-resolved photoemission spectroscopy

ORAL

Abstract

In2Se3 is a widely studied van der Waals (vdW) layered material and its many structural phases have attracted attention for their promise as semiconducting platforms for photovoltaics, use as an isostructural buffer layers in topological Insulator superlattices, and recently as room temperature ferroelectrics1,2. The details of its electronic structure however have not been fully elucidated by experiments. We report on a combined angle-resolved photoemission spectroscopy and density functional theory study which reveals an indirect bandgap with highly anisotropic conduction and valence bands in bulk crystals of commercially obtained β'-phase In2Se3. The n-doped crystals exhibit large effective mass hole bands with maxima slightly offset from Γ, as well as small effective mass electron valleys which sit at Γ and M/M' points, with minima at M/M’ lower in energy by about 0.3eV, resulting in an indirect bandgap of 1.41eV, and a direct bandgap at Γ in excess of 1.7eV.
1Y. Zhou et al., Nano Letters 17, 5508 (2017)
2C. Zheng et al., Science Advances 4, eaar7720 (2018)

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Presenters

  • Michael Fuhrer

    Department of Physics and Astronomy and Centre for Future Low Energy Electronics Technologies, Monash University, Physics and Astronomy, Monash Univ, School of Physics & Astronomy, Monash University, ARC Centre of Excellence in Future Low-Energy Electronics Technologies

Authors

  • Michael Fuhrer

    Department of Physics and Astronomy and Centre for Future Low Energy Electronics Technologies, Monash University, Physics and Astronomy, Monash Univ, School of Physics & Astronomy, Monash University, ARC Centre of Excellence in Future Low-Energy Electronics Technologies

  • James Collins

    Department of Physics and Astronomy and Centre for Future Low Energy Electronics Technologies, Monash University, ARC Centre of Excellence in Future Low-Energy Electronics Technologies

  • Chutian Wang

    ARC Centre of Excellence in Future Low-Energy Electronics Technologies

  • Anton Tadich

    Australian Synchrotron

  • Yuefeng Yin

    ARC Centre of Excellence in Future Low-Energy Electronics Technologies

  • Shujie Tang

    ALS, Lawrence Berkeley National Laboratory, Lawrance Berkeley National Laboratory, Stanford University, SIMES, Stanford University, Advanced Light Source, Lawrence Berkeley National Laboratory

  • Sung-Kwan Mo

    ALS, Lawrence Berkeley National Laboratory, Lawrance Berkeley National Laboratory, Lawrence Berkeley Nat. Lab, Advanced Light Source, Lawrence Berkeley National Laboratory

  • Chang Liu

    Department of Physics and Astronomy and Centre for Future Low Energy Electronics Technologies, Monash University, ARC Centre of Excellence in Future Low-Energy Electronics Technologies

  • Changxi Zheng

    Physics and Astronomy, Monash Univ, ARC Centre of Excellence in Future Low-Energy Electronics Technologies

  • Nikhil Medhekar

    ARC Centre of Excellence in Future Low-Energy Electronics Technologies

  • Mark T Edmonds

    School of Physics and Astronomy, Monash University, Department of Physics and Astronomy and Centre for Future Low Energy Electronics Technologies, Monash University, ARC Centre of Excellence in Future Low-Energy Electronics Technologies