组分渐变过渡层对氮化镓基发光二极管性能的影响

Effect of Graded-Composition Transition Layer on the Performance of GaN-Based Light-Emitting Diodes

针对半导体发光二极管(LED)中普遍存在的效率衰减效应严重影响大注入电流条件下LED发光性能的问题,在传统InGaN/GaN多量子阱LED基础上,设计了组分渐变过渡层结构,引入到量子垒和电子阻挡层界面。模拟计算结果表明:当引入过渡层后,量子垒和电子阻挡层界面处的电子势阱深度和空穴势垒高度减小,有益于有源区载流子浓度的提高,有效提升了量子阱内辐射复合速率,使发光效率衰减现象得到显著改善.研究结果对大功率发光二极管的结构设计和器件研发具有启发作用.

The efficiency-droop phenomenon in semiconductor light-emitting diodes（LEDs） still hinders the further development of high-brightness LEDs for the performance suppression at a high injection current. In this work,based on the conventional InGaN/GaN multiple-quantum-well LEDs,a graded-composition transition layer was designed and inserted between the quantum barrier（QB） and the electron blocking layer（EBL）. The simulation results indicated that with the insert of the transition layer,the depth of electron potential well and the height of hole potential barrier at the interface between the QB and the EBL both decreased,which was conducive to the increase of carrier concentration in the active region,and then lead to an improvement of radiative recombination rates in quantum wells. Hence,the efficiency droop was suppressed. The research is illuminating for the structure design and device development of high-power LEDs.