Efficiency Droop Effect Mechanism in an InGaN/GaN Blue MQW LED

In order to clarify the origin of the efficiency droop effect in InGaN based blue multiple-quantum-well (MQW) light emitting diodes (LEDs), a reasonable model is set up, taking all the possible factor (carrier delocalization, carrier leakage and Auger recombination) into account. By fitting the external quantum efficiency-injection current (η–I) measurements of two LED samples, the validity of the model is demonstrated. The fit results show that the main origin of efficiency droop at a high injection current is carrier leakage. Furthermore it is also indicated that carrier delocalization plays an important role in the efficiency droop effect in those LEDs of large localization degree.