Efficiency droop characteristics in InGaN-based near ultraviolet-to-blue light-emitting diodes

In this study, we prepared InGaN-based light-emitting diodes (LEDs) with peak emissions ranging from 400 to 445nm and investigated their efficiency droop characteristics at injection currents of up to 1 A. We found that the external quantum efficiencies (EQEs) changed dramatically when the critical current increased from 0 to 350 mA, but exhibited a similar negative slope upon increasing the current from 350mA to 1 A. The effects of piezoelectric polarization and different localized states in the active layer of the near UV-to-blue LEDs influenced the peak EQEs and the dramatic decays of the EQE droops at lower injection currents.