[13p-2L-1~11] 9.1 Dielectrics, ferroelectrics

[13p-2L-7] [Young Scientist Presentation Award Speech] Photoluminescence from Point Defects in YAlO₃

〇Takaaki Morimoto¹, Yoshimichi Ohki^1,2 (1.GSASE of Waseda Univ., 2.RIMST of Waseda Univ.)

Keywords:photoluminescence,YAlO3,point defects

Several photoluminescence (PL) bands appear in YAlO₃ single crystal, a promising candidate material for lasers and scintillators, when they are excited by synchrotron radiation as a photon source. Namely, PL appears at 4.2 eV due to the recombination of self-trapped excitons (STEs) and at 5.5 eV due to the recombination of holes and electrons at antisites. Furthermore, PL bands due to transition of 4f orbital electrons also appear at 2.3, 2.6 and 3.1 eV from Er³⁺ and at 1.79, 1.90, 2.02, and 2.10 eV from Eu³⁺. Since the energies are very similar at which the intensity of the two PLs originating in Er³⁺ and STEs become strongest, energy transfer is likely to occur from Er³⁺ to STEs. In addition, one PL peak of the above-mentioned multi-peak PL from Eu³⁺ is due to electric dipolar transition, which becomes forbidden if the site has inversion symmetry. Therefore, Eu³⁺ seems to occupy the Y site with no symmetry of inversion.