俄歇复合、电子泄漏和空穴注入对深紫外发光二极管效率衰退的影响

Impact of Auger Recombination,Electron Leakage and Hole Injection on Efficiency Droop for DUV LEDs

研究了俄歇复合、电子泄漏和空穴注入对深紫外发光二极管(DUV LED)效率衰退的影响。结果表明,当俄歇复合系数从10^(-32) cm^(6)·s^(-1)增大到10^(-30) cm^(6)·s^(-1)时,俄歇复合对效率衰退的影响很小。当俄歇复合系数增大到10^(-29) cm^(6)·s^(-1)时,俄歇复合对效率衰退有显著的影响。然而,对于AlGaN材料而言,俄歇复合系数很难达到10^(-29) cm^(6)·s^(-1)。此外,本研究还发现,即使设置的俄歇复合系数等于10^(-32) cm^(6)·s^(-1),DUV LED的效率衰退依旧随着电子泄漏的增加而增大。因此,这进一步证明了电子泄漏是导致DUV LED效率衰退的主要因素。此外,本工作还证明了空穴注入效率的提高可以有效地抑制DUV LED的效率衰退问题,这主要是由于更多的电子与空穴在量子阱中复合产生了光子,降低了电子从有源区中泄漏的几率。

We reveal the impact of the Auger recombination,electron leakage and hole injection on the efficiency droop for deep-ultraviolet light-emitting diodes(DUV LEDs).According to our results,the minor change of the efficiency droop is caused by the Auger recombination when the Auger recombination coefficients range from 10^(-32) cm^(6)·s^(-1) to 10^(-30) cm^(6)·s^(-1).The Auger recombination induces notable role on the efficiency droop by defining the Auger recombination coefficient of 10^(-29) cm^(6)·s^(-1).However,the large Auger recombination coefficient is not realistic for AlGaN materials.Besides,we find that the efficiency droop becomes significant with the increased electron leakage,even when the adopted Auger recombination coefficient is as small as 10^(-32) cm^(6)·s^(-1).Thus,we can prove electron leakage is a major factor causing the severe efficiency droop for DUV LEDs.We then prove that increasing hole injection can suppress efficiency droop because more electrons can recombine with holes instead of escaping from multiple quantum wells(MQWs).