Structure and white LED properties of Ce-doped YAG-Al 2 O 3 eutectics grown by the micro-pulling-down method

Abstract : A series of Ce-doped YAG-Al₂O₃ eutectics were grown by the micro-pulling-down (μ-PD) method, for the purpose of high power white light emitting diodes. The eutectic structure was investigated. A calibrated integrating sphere spectrometer setup was used to measure the white LED properties of eutectic samples. The CIE color coordinates can be regulated easily by altering the Ce³⁺ doping concentration and sample thickness of the Ce:YAG-Al₂O₃ eutectics. A 1 W white LED device based on Ce:YAG-Al₂O₃ eutectics at a rated current of 350 mA emitted a bright white light with a CIE coordinate of (0.319, 0.334), a luminous efficacy of 83.0 lm W⁻¹ and a D_uv value of 0.003. The results showed that Ce:YAG-Al₂O₃ eutectics have better luminescence properties than commercial powder phosphors at a high current density.