新型AlGaInP系发光二极管饱和特性与寿命的研究

针对AlGaInP系发光二极管(LED)电极阻挡出光、衬底吸收、全反射角小导致器件出光效率低、热积累大、饱和特性差等问题,提出了一种具有复合电流输运增透窗口层、复合DBR反射镜和电流阻挡层结构的新型LED,并测试了其饱和特性和寿命.电流分布模拟显示:新型LED电极下仅存在极小的无效电流;实验结果表明新型LED出光效率高,饱和电流大,饱和电流时光强约为常规LED的3倍,光电性能明显提升.器件饱和特性和老化实验研究显示:新型LED寿命长达17.8×104h,器件内部发热量低,具有高饱和特性和高可靠性,适合在大电流大功率下工作.

Investigation of the saturation characteristic and lifetime of the novel AlGaInP lightemitting diodes

Absorption of substrates, small angle for total reflection, and heat generated by photon blocking of electrode, all can lead to saturation and performance degradation of AlGaInP light emitting diodes(LEDs). In this paper, a novel LED composed of compound current spreading layer, compound DBR reflectors, and current blocking layer, is proposed, the saturation characteristic and lifetime are also tested. Simulation results show that there is only tiny invalid photocurrent through the electrode in the novel LEDs. Experimental results indicate that the novel LEDs have higher extraction efficiency and better saturation characteristics. Saturation current of the novel LEDs is as high as 110 mA, and the light intensity is enhanced by treble at saturation current as compared to the conventional LEDs. The accelerated aging test shows that the lifetime of the novel LEDs is as long as 17.8×10⁴ hours, which means the novel LEDs have high reliability and can be used with high current.