Optical study of Y3-xGdxAl5O12:Ce crystals grown from the melt

Abstract Y3-xGdxAl5O12:Ce (x = 0.6, 1.2, 1.8 in the melt) single crystals were grown from the melt by the Czochralski technique. XRD results shown that crystalline samples contain main garnet Y3-xGdxAl5O12 and additional Al2O3 and GdAlO3 phases. The maximal content of Gd3+ in the main garnet phase was determined at about of 40 at%. The presence of Al2O3 and GdAlO3 phases is explained by the thermal decomposition of Gd3Al5O12. The red-shift of Ce3+ emission with increasing of Gd3+ concentration in Y3-xGdxAl5O12:Ce was found. The latter is in a good agreement with data presented for Y3-xGdxAl5O12:Ce ceramics and powder phosphors. An additional 330–360 nm double-peaked emission observed in Y3-xGdxAl5O12:Ce crystals has been assigned to the 5d→4f radiative transitions of Ce3+ ions in GdAlO3 perovskite phase. In the view of potential application for white light-emitting diodes (WLEDs) light conversion characteristics tests of the Y3-xGdxAl5O12:Ce crystals were performed. The best parameters were obtained for Y1.2Gd1.8Al5O12:Ce sample.