Midgap radiative centers in carbon-enriched hexagonal boron nitride

When serving as a protection tissue and/or inducing a periodic lateral modulation for/in atomically thin crystals, hexagonal boron nitride (hBN) has revolutionized the research on van der Waals heterostructures. By itself, hBN appears as an emergent wide-bandgap material, which, importantly, can be...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2020-06, Vol.117 (24), p.13214-13219
Main Authors: Koperski, Maciej, Vaclavkova, Diana, Taniguchi, Takashi, Novoselov, Kostya S., Potemski, Marek
Format: Article
Language:English
Subjects:
Boron
Boron nitride
Carbon
Crystals
Doping
Emission
Emitters
Energy gap
Heterostructures
Physical Sciences
Physics
Structural analysis
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Summary:When serving as a protection tissue and/or inducing a periodic lateral modulation for/in atomically thin crystals, hexagonal boron nitride (hBN) has revolutionized the research on van der Waals heterostructures. By itself, hBN appears as an emergent wide-bandgap material, which, importantly, can be optically bright in the far-ultraviolet range and which frequently displays midgap defect-related centers of yet-unclear origin, but, interestingly, acting as single-photon emitters. Controlling the hBN doping is of particular interest in view of the possible practical use of this material. Here, we demonstrate that enriching hBN with carbon (C) activates an optical response of this material in the form of a series of well-defined resonances in visible and near-infrared regions, which appear in the luminescence spectra measured under below-bandgap excitation. Two, qualitatively different, C-related radiative centers are identified: One follows the Franck–Condon principle that describes transitions between two defect states with emission/annihilation of optical phonons, and the other shows atomic-like resonances characteristic of intradefect transitions. With a detailed characterization of the energy structure and emission dynamics of these radiative centers, we contribute to the development of controlled doping of hBN with midgap centers.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.2003895117