Indirect bandgap measured in β'-phase In<sub>2</sub>Se<sub>3</sub> 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)
1Y. Zhou et al., Nano Letters 17, 5508 (2017)
2C. Zheng et al., Science Advances 4, eaar7720 (2018)
*This work was supported by the ARC Centre of Excellence in Future Low Energy Electronics Technologies and ARC grant DP150103837.
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Presenters
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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