ИСТИНА

The epitaxial garnet films attract attention because of their excellent scintillation properties. The films can be grown from different supercooled melt solutions such as PbO–B2O3 [1], Bi2O3–B2O3 [2] or BaO–B2O3–BaF2 [3]. Here we report the results of the study of the optical absorption, photoluminescence and scintillation properties of Се-doped (Pb,Gd)3(Al,Ga)5O12 and Се-doped (Bi,Gd)3Ga5O12 epitaxial films. Photoluminescence spectra of Се-doped (Pb,Gd)3(Al,Ga)5O12 films are characterized by a broad non-elementary band peaking at 532 nm (2.33 eV) which corresponds to the radiative 5d-4f transition within the Ce3+ ions. The pulsed cathodoluminescence yield of the most intensive Pb0.01Ce0.02Gd2.97Al3.13Ga1.87O12 film was around 43100 photons/MeV and scintillation light yield was around 20000 photons/MeV under excitation from 133 Ba source. The pulsed cathodoluminescence decay times of this film were 1.8 (1%), 24 (25%), and 60 ns (74%) and scintillation decay times were 3.9 (7%), and 43.6 ns (93%). In the Се-doped (Bi,Gd)3Ga5O12 films the 480 nm (2.58 eV) emission band with excitation maximum at 300 nm (4.13 eV) was observed and ascribed to Bi3+ centers. Also the emission bands at 850 nm (1.46 eV) under excitation at 337 nm (3.68 eV) and at 350 nm (3.54 eV) were observed in the Се-doped (Bi,Gd)3Ga5O12 and (Bi,Gd)3Ga5O12 films. The origin of these bands is discussed. This work was supported in part by the European Social Fund’s Doctoral Studies and Internationalisation Programme DoRa and Estonian Research Council (PUT1081); in part bySubject No AAAA-A18-118022090032-4; in part by M.V. Lomonosov Moscow State University Program of Development. [1] D.A. Vasil’ev, D.A. Spassky, S.I. Omelkov, N.V. Vasil’eva, A.V. Khakhalin, V.G. Plotnichenko, Quantum Electronics 47 (10) (2017) 922 – 926. [2] A. Krasnikov, A. Luchechko, E. Mihokova, M. Nikl, I.I. Syvorotka, S. Zazubovich, Ya. Zhydachevskii, J. Lumin. 190 (2017) 81–88. [3] J. Bok, O. Lalinský, M. Hanuš, Z. Onderišinová, J. Kelar, M. Kučera, Ultramicroscopy 163 (2016) 1–5.