Direct band-gap crossover in epitaxial monolayer boron nitride

Elias, C.; Valvin, P.; Pelini, T.; Summerfield, A.; Mellor, C.J.; Cheng, T.S.; Eaves, L.; Foxon, C.T.; Beton, P.H.; Novikov, S.V.; Gil, B.; Cassabois, G.

Abstract

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 con_rmed 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 reectance spectroscopy with atomic force microscopy to reveal the presence of a direct gap of energy 6.1 eV in the single atomic layers, thus con_rming a crossover to direct gap in the monolayer limit.

Citation

Elias, C., Valvin, P., Pelini, T., Summerfield, A., Mellor, C., Cheng, T., Eaves, L., Foxon, C., Beton, P., Novikov, S., Gil, B., & Cassabois, G. (2019). Direct band-gap crossover in epitaxial monolayer boron nitride. Nature Communications, 10, Article 2639. https://doi.org/10.1038/s41467-019-10610-5

• Journal Article Type: Article
• Acceptance Date: May 22, 2019
• Online Publication Date: Jun 14, 2019
• Publication Date: Jun 14, 2019
• Deposit Date: Jun 3, 2019
• Publicly Available Date: Jun 14, 2019
• Journal: Nature Communications
• Electronic ISSN: 2041-1723
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Article Number: 2639
• DOI: https://doi.org/10.1038/s41467-019-10610-5
• Keywords: General Biochemistry, Genetics and Molecular Biology; General Physics and Astronomy; General Chemistry
• Public URL: https://nottingham-repository.worktribe.com/output/2129788
• Publisher URL: https://www.nature.com/articles/s41467-019-10610-5
• Additional Information: Received: 25 February 2019; Accepted: 22 May 2019; First Online: 14 June 2019; : The authors declare no competing interests.
• Contract Date: Jun 14, 2019