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Nitrogen (N) vacancies inside gallium nitride (GaN) crystals can scatter carriers and degrade the performance of GaN-based devices. Hydrogen (H) termination is an effective approach for eliminating defect levels in Si crystals but is less effective for GaN because the latter requires higher processing temperatures, which causes H to desorb more easily. Fluorine (F) is a potential alternative to H owing to its high chemical reactivity and small atomic radius. In this study, first-principles calculations were used to investigate the effectiveness of F termination of N vacancies in GaN crystals. The calculated density of states and band dispersion diagram indicated that F termination eliminated defect states near the conduction band edge, and electronic states near the band edges became similar to those of intrinsic GaN. These effects were attributed to the bonding between F and Ga dangling bonds. In contrast, while H termination also results in bonding between H and Ga dangling bonds, the bonding states remain near the band edges within the bandgap, so defect levels are not eliminated as effectively as with F termination. These results were attributed to the larger energy difference between the bonding and antibonding states for Ga–F bonds than for Ga–H bonds. These results suggest that F termination can eliminate defect levels caused by N vacancies inside GaN crystals and improve the performance of GaN-based devices.

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  This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Yuki Fujishiro, Tomoe Yayama, Takahiro Nagata, Toyohiro Chikyow, Fumiko Akagi; Effectiveness of fluorine termination at nitrogen vacancies inside gallium nitride crystals based on first-principles calculations. J. Appl. Phys. 28 February 2026; 139 (8): 085703 and may be found at https://doi.org/10.1063/5.0303385.

Keyword: Gallium nitride, First-principles calculations, Fluorine termination, Nitrogen vacancies

Date published: 2026-02-28

Publisher: AIP Publishing

Journal:

• Journal of Applied Physics (ISSN: 00218979) vol. 139 issue. 8 085703

Funding:

• Japan Society for the Promotion of Science 25K08496
• High Performance Computing Infrastructure hp250045

Manuscript type: Author's version (Submitted manuscript)

MDR DOI: https://doi.org/10.48505/nims.6245

First published URL: https://doi.org/10.1063/5.0303385

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Updated at: 2026-04-03 10:13:47 +0900

Published on MDR: 2026-04-03 12:26:41 +0900