Effect of temperature distribution and current crowding on the performance of lateral GaN-based light-emitting diodes

Abstract

Current crowding effect is detrimental for the performance of light-emitting diodes (LEDs), causing non-uniform light emission and local heat generation. In particular, heat generated by non-uniform current distribution can badly influence the performance of LED devices. In this paper, we examine the temperature distributions of lateral InGaN/GaN multiple-quantum-well LEDs in relation to current crowding, using both simulation and experimental results. Simulation results are obtained from a 3-dimensional electrical circuit model consisting of resistances and intrinsic diodes. Temperature and luminance distributions are investigated by images taken by an infrared camera and a charge-coupled-device camera, respectively. Finally, the internal quantum efficiency is taken for each device and compared. We show that the thermal property in the lateral LED is affected by the current crowding due to the local Joule heating nearby electrodes. Therefore, uniform current spreading is very important not only for uniform luminance distribution but also for good thermal property in the LED device. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.