Vacancy-Enhanced N−N Bonding and Deep Level Complex Defect Formation in β−Ga2O3
Abstract
Nitrogen implantation can make β−Ga2O3 semi-insulating, but the atomic origin responsible for carrier trapping remains unresolved. Here, hybrid density functional theory is used to examine complexes derived from an interstitial-substitutional N pair, Ni9−NOI, and effects of nearby O and Ga vacancies on N−N bonding, stability, and electronic states. Within the configurations examined, N atoms favor co-localization. In selected Ga-vacancy-assisted complexes, the N−N distance shortens to 1.09-1.19 mathringA and exhibits electron localization consistent with substantial N−N covalent character. Positive binding energies indicate favorable association relative to separated defects, although many of these complexes have high formation energies and are therefore more likely to be metastable products of implantation than abundant equilibrium defects. Calculated N K-edge XANES spectra for two selected Ga-defect-assisted N−N complexes reveal a pronounced sensitivity of the near-edge π* resonance to the local defect environment, providing an atomistic perspective on the experimentally observed evolution toward molecular N2 during annealing. Projected densities of states and spin-density distributions show localized N-2p- and O-2p-derived states well inside the band gap. These vacancy-assisted N complexes therefore provide an atomistic mechanism for deep carrier trapping and current blocking rather than shallow acceptor doping in β−Ga2O3.
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BibTeX
@misc{shokri2026vacancyenhanced,
title = {{Vacancy-Enhanced $N-N$ Bonding and Deep Level Complex Defect Formation in $β-Ga_2O_3$}},
author = {Asiyeh Shokri and Yevgen Melikhov and Yevgen Syryanyy and Maryna Chernyshova and Iraida N. Demchenko},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.12029},
eprint = {2605.12029},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.12029},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Vacancy-Enhanced N−N Bonding and Deep Level Complex Defect Formation in β−Ga_2O_3
AU - Asiyeh Shokri
AU - Yevgen Melikhov
AU - Yevgen Syryanyy
AU - Maryna Chernyshova
AU - Iraida N. Demchenko
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2605.12029
UR - https://arxiv.org/abs/2605.12029
AB - Nitrogen implantation can make β−Ga_2O_3 semi-insulating, but the atomic origin responsible for carrier trapping remains unresolved. Here, hybrid density functional theory is used to examine complexes derived from an interstitial-substitutional N pair, N_i9−N_OI, and effects of nearby O and Ga vacancies on N−N bonding, stability, and electronic states. Within the configurations examined, N atoms favor co-localization. In selected Ga-vacancy-assisted complexes, the N−N distance shortens to 1.09-1.19 mathringA and exhibits electron localization consistent with substantial N−N covalent character. Positive binding energies indicate favorable association relative to separated defects, although many of these complexes have high formation energies and are therefore more likely to be metastable products of implantation than abundant equilibrium defects. Calculated N K-edge XANES spectra for two selected Ga-defect-assisted N−N complexes reveal a pronounced sensitivity of the near-edge π^* resonance to the local defect environment, providing an atomistic perspective on the experimentally observed evolution toward molecular N_2 during annealing. Projected densities of states and spin-density distributions show localized N-2p- and O-2p-derived states well inside the band gap. These vacancy-assisted N complexes therefore provide an atomistic mechanism for deep carrier trapping and current blocking rather than shallow acceptor doping in β−Ga_2O_3.
ER -