TY - JOUR
T1 - Hexagonal Boron Nitride Crystal Growth from Iron, a Single Component Flux
AU - Li, Jiahan
AU - Wang, Junyong
AU - Zhang, Xiaotian
AU - Elias, Christine
AU - Ye, Gaihua
AU - Evans, Dylan
AU - Eda, Goki
AU - Redwing, Joan M.
AU - Cassabois, Guillaume
AU - Gil, Bernard
AU - Valvin, Pierre
AU - He, Rui
AU - Liu, Bin
AU - Edgar, James H.
N1 - Funding Information:
The crystal growth (J.L. and J.H.E.) in this study was supported by the Materials Engineering and Processing program of the National Science Foundation, Award No. CMMI 1538127. B.L. is grateful for the support by NSF Grant No. CHE-1726332. J.W. and G.E. acknowledge the Singapore National Research Foundation for funding the research under the medium-sized centre programme. G.E. also acknowledges support from the Ministry of Education (MOE), Singapore, under AcRF Tier 3 (Grant No. MOE2018-T3-1-005). X.Z. and J.M.R. acknowledge the support of the National Science Foundation (NSF) through the 2D Crystal Consortium-Materials Innovation Platform (2DCC-MIP) under NSF Cooperative Agreement DMR-1539916. Work at Texas Tech University (G.Y. and R.H.) is supported by an NSF CAREER Grant (No. DMR-1760668). This work was financially supported in France by the contract BONASPES (ANR-19-CE30-0007-02) under the umbrella of the publicly funded Investissements d’Avenir program managed by the French ANR agency.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/4/27
Y1 - 2021/4/27
N2 - The highest quality hexagonal boron nitride (hBN) crystals are grown from molten solutions. For hBN crystal growth at atmospheric pressure, typically the solvent is a combination of two metals, one with a high boron solubility and the other to promote nitrogen solubility. In this study, we demonstrate that high-quality hBN crystals can be grown at atmospheric pressure using pure iron as a flux. The ability to produce excellent-quality hBN crystals using pure iron as a solvent is unexpected, given its low solubility for nitrogen. The properties of crystals produced with this flux matched the best values ever reported for hBN: a narrow Raman E2g vibration peak (7.6 cm-1) and strong phonon-assisted peaks in the photoluminescence spectra. To further test their quality, the hBN crytals were used as a substrate for WSe2 epitaxy. WSe2 was deposited with a low nucleation density, indicating the low defect density of the hBN. Lastly, the carrier tunneling through our hBN thin layers (3.5 nm) follows the Fowler-Nordheim model, with a barrier height of 3.7 eV, demonstrating hBN's superior electrical insulating properties. This ability to produce high-quality hBN crystals in such a simple, environmentally friendly and economical process will advance two-dimensional material research by enabling integrated devices.
AB - The highest quality hexagonal boron nitride (hBN) crystals are grown from molten solutions. For hBN crystal growth at atmospheric pressure, typically the solvent is a combination of two metals, one with a high boron solubility and the other to promote nitrogen solubility. In this study, we demonstrate that high-quality hBN crystals can be grown at atmospheric pressure using pure iron as a flux. The ability to produce excellent-quality hBN crystals using pure iron as a solvent is unexpected, given its low solubility for nitrogen. The properties of crystals produced with this flux matched the best values ever reported for hBN: a narrow Raman E2g vibration peak (7.6 cm-1) and strong phonon-assisted peaks in the photoluminescence spectra. To further test their quality, the hBN crytals were used as a substrate for WSe2 epitaxy. WSe2 was deposited with a low nucleation density, indicating the low defect density of the hBN. Lastly, the carrier tunneling through our hBN thin layers (3.5 nm) follows the Fowler-Nordheim model, with a barrier height of 3.7 eV, demonstrating hBN's superior electrical insulating properties. This ability to produce high-quality hBN crystals in such a simple, environmentally friendly and economical process will advance two-dimensional material research by enabling integrated devices.
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U2 - 10.1021/acsnano.1c00115
DO - 10.1021/acsnano.1c00115
M3 - Article
C2 - 33818058
AN - SCOPUS:85104914049
VL - 15
SP - 7032
EP - 7039
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
IS - 4
ER -