Influence of electron distribution on efficiency droop for GaN-based light emitting diodes

Abstract

By modulating the indium composition in the quantum barriers of InGaN-based LEDs, the influence of electron distribution, electron overflow and Auger recombination on the external quantum efficiency (EQE) and droop effect have been investigated. Experimental results as well as numerical simulations reveal that the electron distribution is the key factor to influence both the peak efficiency and droop effect. The results show that the high electron concentration in the individual quantum well can stimulate the Auger recombination and lead to the droop effect instead of the total effective electron concentration, which is more related to the external quantum efficiency. If we modulate the indium composition in the quantum barriers of the InGaN-based LEDs, a uniform electron distribution can be achieved, which can not only enhance the EQE but also avoid the Auger recombination and improve the droop effect.