Optical properties of green-emitting β-sialon:Eu phosphor-containing silica glasses and their deterioration mechanism

β-sialon:Eu phosphor-containing silica glass was synthesized as a wavelength converter in solid-state lighting. The optical properties and pore density of the sample strongly depended on the sintering temperature. Sintering at a high temperature of 1050 °C led to a severe deterioration of β-sialon:Eu phosphor owing to N2 evaporation, whereas a high conversion efficiency could be achieved by lowering the sintering temperature down to 600 °C. The β-sialon:Eu phosphor-containing silica glass sintered at 600 °C showed a high durability against high-power excitation, making it possible to be used in high-luminosity and high-power solid-state laser lighting.