Crystal growth, structural and optical characterizations of Ce-doped Gd_9.33(SiO₄)₆O₂ single crystals

Abstract

(Ce_x,Gd_1-x)_9.33(SiO₄)₆O₂ single crystals were grown by the µ-PD method. From the structural analysis, the lattice constants increased with increasing Ce concentration. Two nonequivalent crystallographic sites were found for Gd (Ce), 6h and 4f sites. It was revealed that most of Ce locate at Gd(6h) site. XANES analysis revealed while almost all Ce exist as Ce³⁺ in the crystals, a trace amount of Ce exist as Ce⁴⁺. The X-ray excited luminescence spectra of the crystals showed a peak around 400 nm originating from the Ce³⁺ 5d-4f transition. The corresponding decay time is about 25 ns.