GaN基白光LED电流加速老化特性研究

本文对三组Al2O3衬底上生长GaN基蓝光激发黄色荧光粉的白光LED进行了对比电流加速老化实验,老化电流分别是30 mA5、0 mA和70 mA。随着老化电流的增大,GaN基白光LED的光输出功率随时间的衰减速率相对较快;随老化时间的加长,30 mA电流驱动下,GaN基白光LED相对光谱中黄光比重先增加再减小。其原因归结为荧光粉受热降解导致转换量子效率降低和荧光粉本身对短波长的光散射共同作用的结果。最后计算出用于实验的白光LED寿命为457 h。

Research into characteristics of the accelerated degradation GaN/Al2O3 white LEDs

In this paper, the currem accelerated aging experiment on three groups of GaN-based white LEDs produced on the Al2O3 substrate have been performed at 30 mA,50 mA and 70 mA. With the increase of aging current, the light output power of GaN-based white LED he-comes faster with the degradation of time and when the aging time is lengthened, driven by 30mA current, the yellow gravity in the relative light spectrum of GaN-based white LED is increased before being reduced. From the degradation pattern of optical output with respect to time, some preliminary results were obtained, which show that GaN white LEDs grown on Al2O3 substrate exhibit preferable properties. The main factor causing the difference is due to the yellow phosphors for white LED. Finally, the lifetime of the white LEDs used in our experiments was calculated as 457 h.