Modeling of the Point Defect Migration across the AlN/GaN Interfaces-Ab Initio Study

The formation and diffusion of point defects have a detrimental impact on the functionality of devices in which a high quality AlN/GaN heterointerface is required. The present paper demonstrated the heights of the migration energy barriers of native point defects throughout the AlN/GaN heterointerfa...

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Bibliographic Details
Published in:Materials 2022-01, Vol.15 (2), p.478
Main Authors: Hrytsak, Roman, Kempisty, Pawel, Grzanka, Ewa, Leszczynski, Michal, Sznajder, Malgorzata
Format: Article
Language:English
Subjects:
Aluminum nitride
Band theory
Crystal defects
Density functional theory
Electric fields
Energy
Energy bands
Gallium nitrides
Heterostructures
Interfaces
Nitrogen
Organic chemicals
Point defects
Potential barriers
Quality control
Vacancies
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Summary:The formation and diffusion of point defects have a detrimental impact on the functionality of devices in which a high quality AlN/GaN heterointerface is required. The present paper demonstrated the heights of the migration energy barriers of native point defects throughout the AlN/GaN heterointerface, as well as the corresponding profiles of energy bands calculated by means of density functional theory. Both neutral and charged nitrogen, gallium, and aluminium vacancies were studied, as well as their complexes with a substitutional III-group element. Three diffusion mechanisms, that is, the vacancy mediated, direct interstitial, and indirect ones, in bulk AlN and GaN crystals, as well at the AlN/GaN heterointerface, were taken into account. We showed that metal vacancies migrated across the AlN/GaN interface, overcoming a lower potential barrier than that of the nitrogen vacancy. Additionally, we demonstrated the effect of the inversion of the electric field in the presence of charged point defects VGa3- and VAl3- at the AlN/GaN heterointerface, not reported so far. Our findings contributed to the issues of structure design, quality control, and improvement of the interfacial abruptness of the AlN/GaN heterostructures.
ISSN:1996-1944
1996-1944
DOI:10.3390/ma15020478