Thermodynamic Role of Nitrogen Complex in Vacancy Cluster of Group-III Nitrides

This study presents a fundamental investigation into nitrogen complex in group-III nitrides using first-principles calculations, revealing the thermodynamic mechanisms governing vacancy cluster formation under different charge states. We find that nitrogen complexes drive agglomeration of vacancies in (Al, Ga)N through hole compensation and structural reconfiguration, while in n-type conditions and antibonding interactions introduce instability. InN exhibits a distinct behavior, maintaining robust VCs across doping conditions due to the unique role of metal–metal bonding, particularly indium trimer states, which suppress defect-driven instabilities. Our results highlight the intricate interplay between charge states, nitrogen complex, and bonding nature in shaping defect stability, offering new insights into defect engineering for nitride-based semiconductor applications.