MORPHOLOGY AND CATHODOLUMINESCENCE OF Li-DOPED SrTiO_3:Pr~(3+),Ga~(3+), A RED PHOSPHOR OPERATING AT LOW VOLTAGES

摘要

SrTiO_3:Pr,Ga phosphor using Li_2CO_3 as a flux has been investigated as a red phosphor for the application to fluorescent displays operated at low voltage. In SrTiO_3:Pr,Ga system, Pr~(3+)can substitute for Sr~(2+) because the ionic radius of Pr~(3+) almost coincides with that of Sr~(2+). Previous work, it was found by XRF analysis of SrTiO_3:Pr,Ga single crystal that only a small fraction of Pr ions are incorporated in the SrTiO_3 lattice. In the present study, the effect of Li addition into SrTiO_3:Pr,Ga on the cathodoluminescence (CL) properties was examined at low acceleration voltage. Especially, thanks to the liquid phase of Li_2CO_3 during the sintering process, doped Li ions act as a lubricant for the efficient incorporation of Pr ions into SrTiO_3:Pr,Ga lattice. Furthermore, it is found that the Li addition could enhance the generation of the characteristic emission of Pr-activated SrTiO_3 phosphors.