Simulating Efficiency Droop in LED Structures with Polarization and Auger Recombination

What is it about?

The study investigates the influence of polarization and Auger recombination on the internal quantum efficiency (IQE) of GaN-based blue LEDs. The built-in polarization field has a stronger effect on the vertical structures, while the Auger recombination affects both vertical and lateral structures. The lateral structures, both SQW and MQW, generally show better IQE than their vertical counterparts. However, MQW structures show improvement over SQW structures despite the presence of the two droop-causing mechanisms, polarization charge density, and Auger recombination. The degradation effect of Auger recombination is more prominent in vertical MQW structures compared to lateral structures.

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Why is it important?

The study of the influence of polarization and Auger recombination on the efficiency of GaN-based light-emitting diodes (LEDs) is important because it provides insights into the underlying mechanisms causing the efficiency droop in these devices. Understanding these factors can help in the design and growth of LEDs with improved efficiency and performance. Key Takeaways: 1. The efficiency droop in LEDs is influenced by both polarization-induced electric fields and nonradiative recombination mechanisms, such as Auger recombination. 2. The effect of polarization on the efficiency is more pronounced in vertical structures compared to lateral structures. 3. Auger recombination has a stronger influence on the degradation of IQE in vertical multiquantum well structures compared to lateral multiquantum well structures. 4. MQW structures generally show better IQE characteristics than SQW structures, despite the presence of the two droop-causing mechanisms. 5. The IQE of lateral structures is generally better than the vertical structures in both SQW and MQW LEDs.