Acceptor activation model for III-nitride LEDs

摘要

One major contribution to the decay of the internal quantum efficiency (IQE) of InGaN/GaN light emitting diodes (LED) at high current densities is the direct carrier leakage. The direct carrier leakage is mainly caused by electron leakage and is therefore strongly affected by the design of the p-region. In this context we investigate the effect of the acceptor doping on the efficiency. Since acceptor impurities in GaN based materials are subject to a high activation energy we discuss the electronic activation mechanisms as well as activation barrier reduction phenomena. By physics based simulation of a GaN-based LED we demonstrate that the processes reducing the acceptor activation energy affect the IQE and the bias voltage characteristics. We show that by designing the acceptor doping profile the efficiency of GaN-based thin film LEDs may be enhanced.