Effect of an electron beam irradiation on optical and luminescence properties of LiBaAlF6 single crystals

Paper reports the effect of a 10 keV, 110 keV and 10 MeV electron beam irradiation on optical and luminescence properties of LiBaAlF6 (LBAF) single crystals at 10, 90, and 293 K. Five absorption bands at 2.0, 3.2, 4.3, 4.9 and 5.5 eV were revealed in irradiated crystals in the energy range of 1.2-9.5 eV. Several PL emission bands (1.7-1.8, 2.2 and 2.5-3.5 eV) related to defects were found in the luminescence spectra at room temperature, while only one luminescence band at E = 2.2 eV appears at T = 90 K in LBAF crystals after a 10 MeV electron bombardment. The PL excitation spectra and time-response for these emission bands were studied at 10, 90, and 293 K. Thermoluminescence (TL) of irradiated crystals was studied in the temperature range of 90-740 K. New TL glow peaks at 166, 530 and 670 K were revealed and their parameters were determined. Temperature dependence of relative photoluminescence yield recorded monitoring emission at the 1.87 and 2.23 eV in the temperature range from 130 to 450 K, were fitted using five quenching processes related to TL glow peaks revealed in our research. Significant similarity in the manifestation of radiation-induced defects for LBAF and previously studied LiBaF3 single crystals is noted. The effect of an electron beam irradiation on optical and luminescence properties of LBAF single crystals and possible origin of the radiation defects were discussed.