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Title
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Electron paramagnetic resonance study of rare-earth related centres in thermoluminescence phosphors
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Author
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Abstract
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| Rare-earth related centres have been investigated in K2YF5:Tb3+ crystals, exhibiting thermoluminescence (TL) below and above room temperature (RT), using electron paramagnetic resonance (EPR) spectroscopy at Q (34 GHz) and W-band (94 GHz). The spectra have been studied prior to irradiation, after exposure in the kGy range to X-rays at 77 K and subsequent pulse annealing up to 570 K. In addition to Gd3+, previously studied in detail, we identified Er3+ and Yb3+ centres as accidental impurities in as-grown crystals and determined their effective g tensors. The EPR spectra of irradiated and annealed crystals provide evidence for the production of at least three distinct Tb-related trapped hole centres, two of which could definitely be identified as Tb4+. Hence, we prove that the Tb3+ activator ions also act as hole traps in K2YF5. Pulse annealing experiments indicate that the TL above RT results from thermal release of electrons, recombining at these Tb4+ ions. |
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Language
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English
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Source (journal)
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Optical materials. - Amsterdam
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Publication
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Amsterdam
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2011
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ISSN
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0925-3467
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DOI
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10.1016/J.OPTMAT.2011.01.011
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Volume/pages
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33
:6
(2011)
, p. 865-871
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ISI
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000289390000023
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Full text (Publisher's DOI)
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