Direct band-gap crossover in epitaxial monolayer boron nitride.

Autor: Elias C; Laboratoire Charles Coulomb, UMR5221 CNRS-Université de Montpellier, 34095, Montpellier, France., Valvin P; Laboratoire Charles Coulomb, UMR5221 CNRS-Université de Montpellier, 34095, Montpellier, France., Pelini T; Laboratoire Charles Coulomb, UMR5221 CNRS-Université de Montpellier, 34095, Montpellier, France., Summerfield A; School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK., Mellor CJ; School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK., Cheng TS; School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK., Eaves L; School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK., Foxon CT; School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK., Beton PH; School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK., Novikov SV; School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK., Gil B; Laboratoire Charles Coulomb, UMR5221 CNRS-Université de Montpellier, 34095, Montpellier, France., Cassabois G; Laboratoire Charles Coulomb, UMR5221 CNRS-Université de Montpellier, 34095, Montpellier, France. guillaume.cassabois@umontpellier.fr.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2019 Jun 14; Vol. 10 (1), pp. 2639. Date of Electronic Publication: 2019 Jun 14.
DOI: 10.1038/s41467-019-10610-5
Abstrakt: Hexagonal boron nitride is a large band-gap insulating material which complements the electronic and optical properties of graphene and the transition metal dichalcogenides. However, the intrinsic optical properties of monolayer boron nitride remain largely unexplored. In particular, the theoretically expected crossover to a direct-gap in the limit of the single monolayer is presently not confirmed experimentally. Here, in contrast to the technique of exfoliating few-layer 2D hexagonal boron nitride, we exploit the scalable approach of high-temperature molecular beam epitaxy to grow high-quality monolayer boron nitride on graphite substrates. We combine deep-ultraviolet photoluminescence and reflectance spectroscopy with atomic force microscopy to reveal the presence of a direct gap of energy 6.1 eV in the single atomic layers, thus confirming a crossover to direct gap in the monolayer limit.
Databáze: MEDLINE
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