Abstract
In this paper a set of (95-x) P2O5-xB(2)O(3)-4.9Na(2)O-0.1Er(2)O(3) (x = 5-10-15-20 mol%) samples was prepared using a conventional melt-quenching technique. A glass ceramic phase was confirmed by X-ray diffraction. Small crystallites at the B2O3 addition were detected by Raman scattering. The glass containing 20 mol% B2O3 shows a high thermal stability with a value Delta T = Tc-Tg exceeding 100 degrees C. where T-g and T-c are the glass transition and crystallization onset temperatures. The Raman spectroscopy measurement shows that B-O-P bonds were present in the glasses.
From the absorption edge studies, the value of the optical band gap E-opt has been evaluated. The decrease in optical band gap values and consequently the decrease in Urbach's energies confirm the less extension of the localized states within the band gap. As a result, there shall be an increase in the order of the glass network. The variation in optical parameters is owing to the substitution of B2O3 oxides in P2O5-Na2O-Er2O3 glass network. The fundamental absorption edge for all the glasses was analyzed and the Judd-Ofelt parameters (Omega(2), Omega(4) and Omega(6)) were obtained. The PL intensity, the PL life time and the quantum efficiency relative to the I-4(13/2) -> I-4(15/2) (1530 nm) transition of Er3+ were all found to decrease with the addition of B2O3. (C) 2014 Published by Elsevier B.V.