发光学报, 2017, 38 (7): 923, 网络出版: 2017-07-05  

量子阱结构对含V形坑InGaN/GaN蓝光LED效率衰减的影响

Effect of Quantum Well Structure on The Efficiency Droop of V-pits-containing InGaN/GaN Blue LED
作者单位
南昌大学 国家硅基LED工程技术研究中心, 江西 南昌 330047
摘要
使用MOCVD在图形化Si衬底上生长了含V形坑的InGaN/GaN蓝光LED。通过改变生长温度, 生长了禁带宽度稍大的载流子限制阱和禁带宽度稍小的发光阱, 研究了两类量子阱组合对含V形坑InGaN/GaN基蓝光LED效率衰减的影响。使用高分辨率X射线衍射仪和LED电致发光测试系统对LED外延结构和LED光电性能进行了表征。结果表明: 限制阱靠近n层、发光阱靠近p层的新型量子阱结构, 在室温75 A/cm2时的外量子效率相对于其最高点仅衰减12.7% , 明显优于其他量子阱结构的16.3%、16.0%、28.4%效率衰减, 且只有这种结构在低温时(T≤150 K)未出现内量子效率随电流增大而剧烈衰减的现象。结果表明, 合理的量子阱结构设计能够显著提高电子空穴在含V形坑量子阱中的有效交叠, 促进载流子在阱间交互, 提高载流子匹配度, 抑制电子泄漏, 从而减缓效率衰减、提升器件光电性能。
Abstract
V-pits-containing InGaN/GaN blue LEDs were grown on patterned Si substrate by metal-organic chemical vapor deposition (MOCVD). A carrier confinement quantum well(QW)with a larger band gap and a light-emitting QW with a slightly smaller band gap were grown by tuning growth temperature. The effect of QW structure on the efficiency droop performance of V-pits-containing InGaN/GaN blue LED was investigated with some means to mix the two different types of QW. LED epitaxial wafers and LED photoelectric properties were characterized by high-resolution X-ray diffraction and LED test system. For the novel quantum well structure in which the confinement QW close to the n-side and the light-emitting QW close to the p-side, the droop of the external quantum efficiency is only 12.7%, which shows a more significant improvement compared with other QW structures (16.3%, 16.0%, 28.4%). What’s more, only for this kind of structure, the internal quantum efficiency does not decrease sharply with the increasing of drive current at low temperature(T≤150 K). The results show that a reasonable design of QW structure can significantly improve the effective overlap of electron-hole pairs in V-pits-containing InGaN/GaN QWs, promote carriers interaction between wells, and then improve carriers matching degree, inhibit electron leakage, retard efficiency droop, and finally enhance the photoelectric properties of devices.

吕全江, 莫春兰, 张建立, 吴小明, 刘军林, 江风益. 量子阱结构对含V形坑InGaN/GaN蓝光LED效率衰减的影响[J]. 发光学报, 2017, 38(7): 923. LYU Quan-jiang, MO Chun-lan, ZHANG Jian-li, WU Xiao-ming, LIU Jun-lin, JIANG Feng-yi. Effect of Quantum Well Structure on The Efficiency Droop of V-pits-containing InGaN/GaN Blue LED[J]. Chinese Journal of Luminescence, 2017, 38(7): 923.

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