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Title: | Effect of Eu2O3 doping on Ta2O5 crystal growth by the laser-heated pedestal technique |
Author: | Saggioro, B.Z. Andreeta, M.R.B. Hernandes, A.C. MacAtro, M. Peres, M. Costa, F.M. Monteiro, T. Franco, N. Alves, E. |
Keywords: | A1. Crystal structure A1. Doping A1. Heat transfer A2. Laser-heated pedestal growth B1. Oxides B1. Rare earth compounds |
Issue Date: | 15-Dec-2010 |
Publisher: | Elsevier |
Abstract: | High energy band gap hosts doped with lanthanide ions are suitable for optical devices applications. To study the potential of Ta2O5 as a host compound, pure and Eu2O3-doped Ta2O5 crystal fibers were grown by the laser-heated pedestal growth technique in diameters ranging from 250 to 2600 μm and in lengths of up to 50 mm. The axial temperature gradient at the solid/liquid interface of pure Ta2O5 fibers revealed a critical diameter of 2200 μm above which the fiber cracks. X-ray diffraction measurements of the pure Ta2O5 single crystals showed a monoclinic symmetry and a growth direction of [1 1̄ 0]. An analysis of the pulling rate as a function of the fiber diameter for Eu2O3-doped Ta2O5 fibers indicated a well defined region in which constitutional supercooling is absent. Photoluminescence measurements of pure Ta2O5 crystals using excitation above the band gap (3.8 eV) were dominated by a broad unstructured green band that peaked at 500 nm. Three Eu3+-related optical centers were identified in the doped samples with nominal concentrations exceeding 1 mol%. Two of these centers were consistent with the ion in the monoclinic phase with different oxygen coordinations. The third one was visible in the presence of the triclinic phase |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/6082 |
DOI: | 10.1016/j.jcrysgro.2010.09.083 |
ISSN: | 0022-0248 |
Appears in Collections: | DFis - Artigos I3N-FSCOSD - Artigos |
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