Effects of O[sub 2] Partial Pressure and Ga Atmosphere on the Luminescence of Native Defects in β–Ga[sub 2]O[sub 3] Phosphor

, a native defect luminescent material with blue emission, was fabricated by annealing powders under various partial pressures or in Ga metal atmosphere. Annealing under low partial pressure favors the photoluminescence (PL), which indicates that should be one of the luminescence centers in this phosphor. Annealing in Ga metal atmosphere reduced the PL intensity, which indirectly suggests that or defect cluster might be another luminescent center. Electron paramagnetic resonance (EPR) measurements verified the existence of single ionized oxygen vacancy . An EPR signal with and four hyperfine lines was observed, which is considered to be related to and the hyperfine interaction parameter is . Furthermore, the correlations between PL intensity and the densities of as well as were studied. At present, although we can not clarify whether exists as or , , and may act as donors, whereas or may act as accepters for the luminescence.