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 |
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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. |
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ISSN: | 0947-8396 1432-0630 |
DOI: | 10.1007/s00339-010-5713-1 |