InGaN基LED中极化效应对发光特性的影响

Influence of Polarization Effect on the Luminescence Properties of InGaN-Based LEDs

主要利用电致发光的实验手段,研究了极化效应对InGaN基LED器件发光特性的影响。实验中发现,InGaN基LED器件的峰位随注入电流的增加产生了先蓝移后红移的现象,蓝光和绿光LED分别蓝移3 nm和8 nm;而AlGaInP基红光LED器件的峰位仅红移。进一步研究发现,InGaN基LED的外量子效率在注入电流为50 mA处开始剧烈下降,AlGaInP基LED的外量子效率在100 mA处才开始缓慢下降,并且两者呈现不同的下降规律。通过与模拟结果对比发现,InGaN基LED的效率在下降开始阶段与俄歇复合引起的效率下降规律类似。以上实验结果表明,InGaN基LED器件中存在极化电场,且该极化电场会对LED器件的效率衰减产生促进作用。

The influence of polarization effect on the luminescence characteristics of InGaN-based LEDs was researched by the experimental means of electroluminescence.It is found that the peak position of the InGaN-based LED has a blue shift before a red shift with the increase of the injection current,while the peak position of the AlGaInP-based red LED only has a red shift.The peak positions of the blue and green LEDs are blue-shifted by 3 nm and 8 nm,respectively.By further study,it is found that the external quantum efficiency of the InGaN-based LED decreases drastically at the injection current of 50 mA,and the external quantum efficiency of the AlGaInPbased LED begins to decrease slowly at 100 mA.They show different decrease trends.Compared with the simulation results,it is found that the InGaN-based LED exhibits an efficiency decline trend similar to the Auger recombination induced efficiency droop at the beginning of the efficiency decline.The experimental results show that the polarization electric field exists in the InGaNbased LED and can promote the efficiency droop in the InGaN-based LEDs.