Analysis of efficiency droop in 280-nm AlGaN multiple-quantum-well light-emitting diodes based on carrier rate equation

Abstract

The efficiency droop in 280-nm AlGaN multiple-quantum-well (MQW) ultraviolet (UV) light-emitting diodes (LEDs) is analyzed using the carrier rate equation. It is shown that the internal quantum efficiency (eta(IQE)), injection efficiency (eta(inj)), light-extraction efficiency (eta(LEE)), Shockley-Read-Hall recombination coefficient (A), and Auger coefficient (C) can be determined by the carrier rate equation using the theoretical radiative recombination coefficient (B), experimentally measured wavelength spectrum, and external quantum efficiency (eta(EQE)). The results show that the carrier spillover from the MQWs to the p-AlGaN layer is the main cause of the efficiency droop. (C) 2015 The Japan Society of Applied Physics.