Cathodoluminescence change of Y2O3:Eu phosphors by incorporation of Zn ions

Zn-doped Y2O3:Eu phosphors have been studied as potential red phosphors for application to field emission displays. Cathodoluminescence intensities of Zn-doped Y2O3:Eu phosphors sintered at 1000 and 1200 °C increased compared with Zn-undoped phosphor under relatively low excitation energies. However, when the excitation energies are increased, the intensities of the Zn-doped Y2O3:Eu phosphors varied with the doping amount of Zn ions. Also, it was found that the Zn ions form a solid solution with the lattice of Y2O3:Eu phosphors when the molar ratio of Zn/(Y+Eu) is less than 0.25. From consideration of defect chemistry and cathodoluminescence results, it is understood that the changes of cathodoluminescence intensities are correlated with both the dead layer of the phosphor and the diffusivity of Zn ions in the phosphor lattice. Cathodoluminescence of the Zn-doped Y2O3:Eu phosphors is increased by cooperation of the Zn ions with the dead layers.