Diversity of split Ga vacancies in β-Ga2O3

Positron annihilation spectroscopy has been applied to study the vacancy-type defects in a wide range of β-Ga₂O₃ bulk crystals and thin films. The experimental data show that all studied samples contain high concentrations of Ga vacancies in a split vacancy configuration. These split Ga vacancies are observed also with other experimental techniques, and theoretical calculations predict that their formation energies are lower than those of other vacancy configurations. The exact structure of the split Ga vacancies appears to vary across samples.