Inserting a p-InGaN layer before the p-AlGaN electron blocking layer suppresses efficiency droop in InGaN-based light-emitting diodes

Abstract

In this study, we observed a dramatic decrease in the efficiency droop of InGaN/GaN light-emitting diodes after positioning a p-InGaN insertion layer before the p-AlGaN electron-blocking layer. The saturated external quantum efficiency of this device extended to 316 mA, with an efficiency droop of only 7% upon increasing the operating current to 1 A; in contrast, the corresponding conventional light-emitting diode suffered a severe efficiency droop of 42%. We suspect that the asymmetric carrier distribution was effectively mitigated as a result of an improvement in the hole injection rate and a suppression of electron overflow.