Luminescence characteristics of single crystals (SC) and single crystalline films (SCF) of YAlO3 and YAlO3:Ce were studied at 4.2 to 300K under photo-excitation in the 4 to 20eV energy range. The origin and structure of the intrinsic and impurity defects responsible for various exciton-related emission and excitation bands were identified. The ≈5.6eV emission of YAlO3 SCF was ascribed to the self-trapped excitons. In YAlO3 SC, the dominating 5.63 and 4.12eV emissions were attributed to excitons localized at the isolated antisite defect YAl3+ and at the YAl3+ defect associated with the nearest-neighbouring oxygen vacancy, respectively. The thermally stimulated release of the electrons, trapped at these defects, took place around 200 and 280K, respectively. The presence of YAl3+-related defects and isolated oxygen vacancies (AlO5 units) in YAlO3 SC was confirmed by NMR measurements. The formation energies of various YAl3+-related defects were calculated within the density functional theory. The influence of various intrinsic and impurity defects on the luminescence characteristics of Ce3+ centres was clarified.

Time-Resolved Spectroscopy of Exciton States in Single Crystals and Single Crystalline Films of YAlO3 and YAlO3:Ce. V.Babin, V.Gorbenko, I.Kondakova, T.Kärner, V.V.Laguta, M.Nikl, S.Zazubovich, Y.Zorenko: Journal of Physics D, 2011, 44[31], 315402