%0 Journal Article
%T Cathodoluminescence spectroscopy of monolayer hexagonal boron nitride
%+ Tohoku University [Sendai]
%+ School of Physics and Astronomy [Nottingham]
%+ Axe Physique de l'Exciton, du Photon et du Spin (L2C) (PEPS)
%A Shima, Kohei
%A Cheng, T.S.
%A Mellor, Christopher J.
%A Beton, Peter
%A Elias, Christine
%A Valvin, Pierre
%A Gil, Bernard
%A Cassabois, Guillaume
%A Novikov, Sergei
%A Chichibu, Shigefusa
%Z This work was supported in part by “Crossover Alliance to Create the Future with People, Intelligence, and Materials” and JSPS KAKENHI (Grant Nos. JP16H06427, JP17H02907, JP20K20993, and JP22H01516) by Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. This work was also supported in part by the Engineering and Physical Sciences Research Council UK (Grant Nos. EP/K040243/1, EP/P019080/1, and EP/V05323X/1).
%< avec comité de lecture
%@ 2045-2322
%J Scientific Reports
%I Nature Publishing Group
%V 14
%N 1
%P 169
%8 2024-01-02
%D 2024
%R 10.1038/s41598-023-50502-9
%K Two-dimensional materials
%Z Physics [physics]/Condensed Matter [cond-mat]Journal articles
%X Cathodoluminescence (CL) spectroscopy is a suitable technique for studying the luminescent properties of optoelectronic materials because CL has no limitation on the excitable bandgap energy and eliminates ambiguous signals due to simple light scattering and resonant Raman scattering potentially involved in the photoluminescence spectra. However, direct CL measurements of atomically thin two-dimensional materials have been difficult due to the small excitation volume that interacts with high-energy electron beams. Herein, distinct CL signals from a monolayer hexagonal BN (hBN), namely mBN, epitaxial film grown on a graphite substrate are shown by using a CL system capable of large-area and surface-sensitive excitation. Spatially resolved CL spectra at 13 K exhibited a predominant 5.5-eV emission band, which has been ascribed to originate from multilayered aggregates of hBN, markedly at thicker areas formed on the step edges of the substrate. Conversely, a faint peak at 6.04 ± 0.01 eV was routinely observed from atomically flat areas, which is assigned as being due to the recombination of phonon-assisted direct excitons of mBN. The CL results support the transition from indirect bandgap in bulk hBN to direct bandgap in mBN. The results also encourage one to elucidate emission properties of other low-dimensional materials by using the present CL configuration.
%G English
%2 https://hal.science/hal-04791841v1/document
%2 https://hal.science/hal-04791841v1/file/23mBNCL_SciRep_230713_submitted.pdf
%L hal-04791841
%U https://hal.science/hal-04791841
%~ CNRS
%~ L2C
%~ UNIV-MONTPELLIER
%~ UM-2015-2021
%~ UM-EPE