Ce3+-doped yttrium aluminum gallium garnet (YAGG:Ce3+), which is a green-emitting phosphor, was synthesizedby solid state reaction using α-phase or γ-phase of nano-sized Al2O3 as the Al source. The processing conditions and thechemical composition of phosphor for the maximum emission intensity were optimized on the basis of emission intensity undervacuum UV excitation. The optimum heating temperature for phosphor preparation was 1550oC. Photoluminescence propertiesof the synthesized phosphor were investigated in detail. From the excitation and emission spectra, it was confirmed that theYAGG:Ce3+ phosphors effectively absorb the vacuum UV of 120-200nm and emit green light positioned around 530nm. Thecrystalline phase of the alumina nanoparticles affected the particle size and the luminescence property of the synthesizedphosphors. Nano-sized γ-Al2O3 was more effective for the achievement of higher emission intensity than was nano-sized α-Al2O3. This discrepancy is considered to be because the diffusion of Al3+ into Y2O3 lattice is dependent on the crystalline phaseof Al2O3, which affects the phase transformation of YAGG:Ce3+ phosphors. The optimum chemical composition, having themaximum emission intensity, was (Y2.98Ce0.02)(Al2.8Ga1.8)O11.4 prepared with γ-Al2O3. On the other hand, the decay time of theYAGG:Ce3+ phosphors, irrespective of the crystalline phase of the nano-sized alumina source, was below 1 ms due to theallowed 5d→4f transition of the Ce3+ activator.

• 우미혜 | Wu, Mi-Hye
• 최성호 | 최성호
• 정하균 | 정하균