Analysis of processes limiting quantum efficiency of AlGaInN LEDs at high pumping

In this paper we argue that the quenching of external quantum efficiency (EQE) with increase of current typically observed for AlInGaN LEDs is caused by reduction of injection efficiency. It is shown as a result of numerical simulations that the current blocking AlGaN layer is inefficient at high current density due to piezoelectric field of GaN/AlGaN interface. The results of numerical simulation are in good agreement with experimental dependence of EQE on pumping. A new design of LED heterostructure is proposed, for which the EQE quenching is not expected. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.