Hexagonal Boron Nitride Crystal Growth from Iron, a Single Component Flux.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33818058.
- Also identified by DOI 10.1021/acsnano.1c00115.
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Abstract
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 E<sub>2g</sub> vibration peak (7.6 cm<sup>-1</sup>) and strong phonon-assisted peaks in the photoluminescence spectra. To further test their quality, the hBN crytals were used as a substrate for WSe<sub>2</sub> epitaxy. WSe<sub>2</sub> 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.