Reduction of vacancy defects induced by thermal annealing in β-Ga2O3 epilayer

The effects of annealing in oxygen atmosphere of β-Ga2O3 epilayers were investigated by X-ray photoelectron spectroscopy, photoluminescence and Fourier-transform infrared spectroscopy. The increasing proportions of Ga3+ and OL (lattice oxygen) signifies the reduction of VO as the annealing temperature rising. The variations of the photoluminescence emissions demonstrate the improvement of the crystal quality and reduction of VO(1), VO(2) and VGa. VO and VGa are filled with oxygen atoms and gallium atoms after annealing, mainly attributed to the bonds constructions of Ga (1)–O (1) and Ga (1)–O (2) in GaO4 tetrahedra. These results offer detailed information and guidelines for removing intrinsic point defects in β-Ga2O3.