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Luminescence and point defects in cerium-doped lutetium scandium orthoborate crystals

Research paper by Yuntao Wu, Dongzhou Ding, Yabin Wang, Shangke Pan, Fan Yang, Guohao Ren

Indexed on: 25 Mar '11Published on: 25 Mar '11Published in: Applied Physics A



Abstract

Cerium-doped lutetium scandium orthoborate single crystals as potential scintillation materials were grown by the floating zone (FZ) method for the first time and the Czochralski (Cz) grown crystal was used for comparison. In this paper, the representative composition Lu0.5Sc0.5BO3:0.5at%Ce (abbreviated as LSBO:Ce) was selected as the research target. The phase structure of FZ-grown LSBO:Ce crystal was characterized by X-ray diffraction and its optical properties were investigated using photoluminescence emission (PL), excitation (PLE), radioluminescence (RL) spectra. The defect properties of LSBO:Ce crystals were studied by thermoluminescence (TL) as a function of temperature (300–600 K). The glow curve of FZ-grown LSBO:Ce crystal shows three TSL peaks, at 350, 400, 552 K, corresponding to a trap depth of 0.99, 1.14 and 1.50 eV, respectively. Based on UV-irradiation TL measurements and air-annealing experiments, the former two kinds of traps could be ascribed to the radiation-induced defects and the third kind originated from the oxygen vacancies formed during crystal growth. These defects also existed in the Cz-grown LSBO:Ce crystal.