Infrared emission and defect centres in Er and Yb codoped Y3Al5O12 phosphors

YAG phosphor powders doped/codoped with Er 3+ /(Er 3+  + Yb 3+ ) have been synthesised by using the solution combustion method. The effect of direct pumping into the 4 I 11/2 level under 980 nm excitation of doped/codoped Er 3+ /Yb 3+ −Er 3+ in Y 3 Al 5 O 12 (YAG) phosphor responsible for an infrare...

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Veröffentlicht in:Applied physics. A, Materials science & processing Materials science & processing, 2010-09, Vol.100 (4), p.1123-1130
Hauptverfasser: Singh, Vijay, Rai, Vineet Kumar, Watanabe, S., Gundu Rao, T. K., Ledoux-Rak, Isabelle, Kwak, Ho-Young
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Sprache:eng
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Zusammenfassung:YAG phosphor powders doped/codoped with Er 3+ /(Er 3+  + Yb 3+ ) have been synthesised by using the solution combustion method. The effect of direct pumping into the 4 I 11/2 level under 980 nm excitation of doped/codoped Er 3+ /Yb 3+ −Er 3+ in Y 3 Al 5 O 12 (YAG) phosphor responsible for an infrared (IR) emission peaking at ∼1.53 μm corresponding to the 4 I 13/2 → 4 I 15/2 transition has been studied. YAG exhibits three thermally-stimulated luminescence (TSL) peaks at around 140°C, 210°C and 445°C. Electron spin resonance (ESR) studies were carried out to identify the centres responsible for the TSL peaks. The room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0176 is identified as O − ion, while centre II with an isotropic g-factor 2.0020 is assigned to an F + centre (singly ionised oxygen vacancy). An additional defect centre is observed during thermal-annealing experiments and this centre (assigned to F + centre) seems to originate from an F-centre (oxygen vacancy with two electrons) and these two centres appear to correlate with the observed high-temperature TSL peak in YAG phosphor.
ISSN:0947-8396
1432-0630
DOI:10.1007/s00339-010-5713-1