Preparation and up-conversion luminescence of Er-doped yttria stabilized zirconia single crystals

Abstract

High-quality yttria-stabilized zirconia (YSZ) single crystals doped with different concentrations of Er2O3 were grown by the optical floating zone method. The cubic phase of ZrO2 was retained when Er3+ partially replaced Y3+ in the YSZ matrix. Up-conversion luminescence was observed when the crystals were excited by a 980 nm laser diode. The optical power curve was obtained by plotting the up-conversion luminescence intensity against the laser power, and both the green and red light up-conversion were shown to involve two photons. Seven characteristic visible and three infrared absorption peaks were observed in the absorption spectrum of the 1.50 mol% Er2O3: YSZ. The up-conversion spectra produced three prominent peaks at 547(green), 561 (green) and 679 (red) nm. Green and red light maxima were observed with Er2O3 concentrations of 1.5 mol% and 0.5 mol%, respectively. Oscillator strength parameters Ωt (t = 2, 4, 6) were determined using the Judd-Ofelt theory and Ω2 = 9.90 × 10−20 cm2, Ω4 = 2.92 × 10−20 cm2, Ω6 = 3.32 × 10−20 cm2. The Ω4/Ω6 ratio (0.88), which is the key parameter for laser performance of reactive matrix materials, indicates that Er3+-doped YSZ has potential laser applications.