- Monolayer Boron Nitride: Hyperspectral Imaging in the Deep Ultraviolet doi link

Auteur(s): Rousseau A., Ren Lei, Durand A., Valvin P., Gil B., Watanabe Kenji, Taniguchi Takashi, Urbaszek Bernhard, Marie Xavier, Robert Cédric, Cassabois G.(Corresp.)

(Article) Publié: Nano Letters, vol. 21 p.10133 (2021)
Texte intégral en Openaccess : openaccess

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DOI: 10.1021/acs.nanolett.1c02531
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The optical response of 2D materials and their heterostructures is the subject of intense research with advanced investigation of the luminescence properties in devices made of exfoliated flakes of few- down to one-monolayer thickness. Despite its prevalence in 2D materials research, hexagonal boron nitride (hBN) remains unexplored in this ultimate regime because of its ultrawide bandgap of about 6 eV and the technical difficulties related to performing microscopy in the deep-ultraviolet domain. Here, we report hyperspectral imaging at wavelengths around 200 nm in exfoliated hBN at low temperature. In monolayer boron nitride, we observe direct-gap emission around 6.1 eV. In marked contrast to transition metal dichalcogenides, the photoluminescence signal is intense in few-layer hBN, a result of the near unity radiative efficiency in indirect-gap multilayer hBN.