白光LED用Ce:YAG单晶的光学性能与掺杂浓度分析

Studies on Optical Properties and Ce Concentration of Ce:YAG Single Crystal for WLEDs

采用提拉法生长Ce：YAG单晶,通过X射线衍射和激发发射光谱对其晶相结构和光谱特性进行了表征,研究了Ce：YAG单晶封装白光LED的最佳掺杂浓度.在455 nm蓝光激发下, Ce：YAG单晶的发射光谱可由中心波长526 nm（5d12 EgГ8g→4f12 F7/2Г8u）的宽发射带（500~650 nm）组成；激发光谱由343 nm （4f12F5/2Г7u→5d12EgГ7g）和466 nm（4f12F5/2Г7u→5d12EgГ8g）2个激发峰组成；Stokes位移为2448 cm-1, Huang-Rhys因子为6.12.研究结果表明, Ce：YAG单晶中Ce离子掺杂浓度与封装的白光LED之间有对应关系,在650 nm红粉调节下Ce离子最佳掺杂浓度范围为0.034~0.066.

Ce：YAG single crystal for white light emitting diode（ WLED） was grown by Czochralski method. The structure and optical properties of samples were characterized by X-ray diffraction（ XRD） and photolumi-nescence spectra. Ce ： YAG single crystal shows a 500-650 nm broad emission band around 526 nm （5d1 2EgГ8g→4f1 2F7/2Г8u） under blue light of 455 nm. The excitation spectrum of Ce：YAG single crystal is made up of 343 nm（4f1 2F5/2Г7u→5d1 2EgГ7g） and 466 nm（4f1 2F5/2Г7u→5d1 2EgГ8g） excitation peaks. The Stokes shift is 2448 cm-1 . The Huang-Rhys parameter is 6.12 . The Ce concentration of Ce：YAG single crys-tal is related with colour coordinate of WLEDs made by Ce：YAG single crystal with the red phosphor （ 650 nm）, a best concentration range of Ce in Ce：YAG single crystal is 0.034-0.066.