Temperature dependence of photoluminescence of α-Ga2 O3 powders

In this investigation, alpha-Ga2O3 powder is synthesized by the heat treatment of gallium oxyhydroxide (GaOOH) under O-2 and NH3 gas flow conditions, and the temperature dependence of its photoluminescence characteristics is systematically examined, for the first time. A new UV emission band with high intensity and narrow bandwidth is observed at 3.469 eV for the alpha-Ga2O3 powders synthesized in NH3. This new luminescence band thermally relaxes and decays when the temperature is higher than 130 K, which is ascribed to the radiative recombination of the shallow donor-bound excitons. These phenomena are thought to be due to the nitrogen atoms incorporated into the alpha-Ga2O3 crystal lattice from NH3 gases during the heat treatment of GaOOH.