Effect of substrate properties on luminescence of white ZnGa ₂O₄ phosphor

The variations in the crystallization and luminescence characteristics of ZnGa₂O₄ phosphor screens deposited on various substrates were investigated. The ZnGa₂O₄ phosphor deposited on Corning glass, indium tin oxide glass and Si substrates was polycrystalline. However, when a ZnO buffer layer was prepared, it was amorphous; it was polycrystalline after annealing at a temperature higher than 300°C. The optimal cathodoluminescence was caused by the low backscattering of electrons, a large emission area, and the specific crystallization of the ZnGa ₂O₄ phosphor grown on the ITO glass substrate. When a ZnO buffer layer was prepared, small ZnGa₂O₄ grains were grown; consequently, the emission area and CL intensity increased. Resistivity measurement revealed that the conductivity and cathodoluminescence are improved by thermal annealing.