Split Ga vacancies in <i>n</i>-type and semi-insulating β-Ga2O3 single crystals

Abstract

We report a positron annihilation study using state-of-the-art experimental and theoretical methods in n-type and semi-insulating β-Ga2O3. We utilize the recently discovered unusually strong Doppler broadening signal anisotropy of β-Ga2O3 in orientation-dependent Doppler broadening measurements, complemented by temperature-dependent positron lifetime experiments and first principles calculations of positron–electron annihilation signals. We find that split Ga vacancies dominate the positron trapping in β-Ga2O3 single crystals irrespective of the type of dopant or conductivity, implying concentrations of at least 1×1018 cm−3.