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.