Investigation on the performance of multi-quantum barriers in InGaN/GaN multi-quantum well light-emitting diodes

摘要

We introduce a structure of multi-quantum barriers (MQBs) into the multi-quantum well (MQW) heterostructures to improve the performance in light-emitting diodes. The InGaN/GaN MQW LEDs with and without MQBs were prepared by metal-organic vapor phase epitaxy system. The electroluminescence measurements were carried out over a temperature range from 20 to 300 K and an injection current level from 10 to 100 mA. According to the experimental results of the InGaN/GaN MQW LEDs, we observe the enhancement of carrier confinement in the active layer and the inhibited carrier leakage over the barrier to the p-GaN regions for the sample with MQBs, which we attribute to the increase of effective barrier heights due to the quantum interference of the electrons within MQBs. In addition, the variations of electroluminescence external quantum efficiency as a function of injection current at various temperatures are also obtained for the samples. It is observed that the sample possessing MQBs exhibit less sensitive temperature dependence and indeed improve the radiative efficiency.