[14a-411-1~10] 13.9 Optical properties and light-emitting devices

▼ [14a-411-8] 3D-CL analysis for core-shell structured SiAlON phosphors

〇(PC)Yujin Cho¹, Benjamin Dierre², Takashi Takeda¹, Shu-Xing Li¹, Rong-Jun Xie¹, Naoto Hirosaki¹, Takashi Sekiguchi¹ (1.NIMS, 2.T.U.Delft)

Keywords:Cathodoluminescence, Phosphors, Single particle analysis

Phosphors with high thermal stability and small thermal quenching are crucial for fabricating high-power LEDs. In this respect, rare-earth doped SiAlON phosphors are promising materials due to their stable chemical bonding. However further improvement are still required to suppress degradation of the phosphors during fabrication or devices operation. Recently, we have found some SiAlON phosphors has occasionally possessed the core-shell structures during sintering and the thermal and chemical stability have been improved [1,2]. Such improvements are attributed to the surface layer acting as a protective coating for the luminescent core body. A better understanding of core-shell structured phosphors is thus important for the development of improved phosphors.Recently, we have developed 3-D CL spectral imaging for characterization of such core shell structured particle. This technique uses the CCD detector to take the whole CL spectrum emitted per one pixel and express its intensity as a contrast of the image.Fig. 1 shows 3D-CL spectral image of cross-sectioned CaAlSiN₃:Eu²⁺ single particle embedded in the ceramic plate. The spectral image showed that the CL luminescence was distributed from 500~700 nm with the highest intensity at 650 nm. When we pick out the images at 550nm and 650nm, the 550nm is mainly distributed at the surface layer while the 650nm is stronger at the core matrix in the particle. EPMA and TEM results indicated that the surface layer was attributed to the CaAlSiON.