The Winner Takes It All: Carbon Supersedes Hexagonal Boron Nitride with Graphene on Transition Metals at High Temperatures.
Small
; 18(49): e2205184, 2022 Dec.
Article
em En
| MEDLINE
| ID: mdl-36319466
ABSTRACT
The production of high-quality hexagonal boron nitride (h-BN) is essential for the ultimate performance of 2D materials-based devices, since it is the key 2D encapsulation material. Here, a decisive guideline is reported for fabricating high-quality h-BN on transition metals. It is crucial to exclude carbon from the h-BN related process, otherwise carbon prevails over boron and nitrogen due to its larger binding energy, thereupon forming graphene on metals after high-temperature annealing. The surface reaction-assisted conversion from h-BN to graphene with high-temperature treatments is demonstrated. The pyrolysis temperature Tp is an important quality indicator for h-BN/metals. When the temperature is lower than Tp , the quality of the h-BN layer is improved upon annealing. While the annealing temperature is above Tp , in case of carbon-free conditions, the h-BN disintegrates and nitrogen desorbs from the surface more easily than boron, eventually leading to clean metal surfaces. However, once the h-BN layer is exposed to carbon, graphene forms on Pt(111) in the high-temperature regime. This not only provides an indispensable principle (avoid carbon) for fabricating high-quality h-BN materials on transition metals, but also offers a straightforward method for the surface reaction-assisted conversion from h-BN to graphene on Pt(111).
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MEDLINE
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En
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2022
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Article
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