Effects of current spreading on the performance of GaN-based light-emitting diodes

Effects of current spreading on the performance of multiple quantum well (MQW) GaN/InGaN light-emitting diodes (LEDs) were investigated. For the theoretical prediction of device performance, we developed a model using two device-design parameters, which consist of the applied current density and the effective length for the lateral current path. A comparison of the theoretical and experimental results clearly showed that the reliability characteristics and the optical efficiency of device are heavily dependent on the applied current density. In addition, the effective length for the lateral current path was found to have a profound effect on the uniform current spreading. Based on these findings, an ideal geometrical design of the highly efficient LED is proposed.