Lanthanoid-doped quaternary garnets as phosphors for high brightness cathodoluminescence-based light sources
M. Korjik, A. Bondarau, G. Dosovitskiy, Valery Dubov, K. Gordienko, Petr Karpuk, I. Komendo, Daria Kuznetsova, V. Mechinsky, В. А. Пустоваров, V. Smyslova, Dmitry Tavrunov, V. M. Retivov
Abstract
Gadolinium-yttrium- aluminum-gallium garnets (GYAGG) doped and codoped with Eu, Tb, and Ce were manufactured as ceramics to develop long-wavelength phosphors for high-brightness white light sources based on cathodoluminescence (CL). The CL light yield (LY) of Tb-doped ceramics at high-intensity electron beam excitation is shown to be more than twice as high as that of the conventional phosphor YAG:Ce, whereas codoping with Eu to redshift the chromaticity results in reducing the LY approximately to the level of YAG:Ce. The LY might be substantially improved by using a mix of Tb- and Eu-doped GYGAG powders instead of a single codoped GYGAG to produce ceramic phosphor. The high LY is explained by favorable contribution of Gd sublattice in excitation transfer to activator ions. Chromaticity of phosphors GYGAG:Tb, Eu can be tuned in a wide range by varying the ratio of Tb to Eu concentration. They are radiation resistant and stabile in the temperature range from 300 to 450 K.