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Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

preprint
revised on 04.06.2019 and posted on 04.06.2019 by Henrik Pedersen, Björn Alling, Hans Högberg, Annop Ektarawong
Thin films of boron nitride (BN), particularly the sp2-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp2-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

Funding

This work was supported by the Swedish Foundation for Strategic Research (SSF) (Contract No. IS14-0027). H.P., B.A., and H.H. acknowledge financial support from the Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009-00971) B.A. acknowledge financial support from SSF through the Future Research Leaders 6 grant and from the Swedish Research Council (VR) through grant No. 2014-6336 and by Marie Sklodowska Curie Actions, Cofund, Project INCA 600398. A.E.acknowledges financial support from Kungl. Ingenjörsvetenskapsakademiens Hans Werthén-Fond. All calculations were carried out using supercomputer resources provided by the Swedish National Infrastructure for Computing (SNIC) performed at the National Supercomputer Centre (NSC) and the Center for High Performance Computing (PDC).

Potentials of Boron Nitride thin films in electronic devices

Swedish Foundation for Strategic Research

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SFO-Mat-LiU No. 2009-00971

VR 2014-6336

INCA 600398

History

Email Address of Submitting Author

henrik.pedersen@liu.se

Institution

Linköping University

Country

Sweden

ORCID For Submitting Author

0000-0002-7171-5383

Declaration of Conflict of Interest

No conflicts

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