Advantages of concave quantum barriers in AlGaN deep ultraviolet light-emitting diodes
Advantages of concave quantum barriers in AlGaN deep ultraviolet light-emitting diodes
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DOI：
10.1117/12.2650411
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发表时间：
2023-03
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通讯作者：
B. Jain;Mano Balo Sankar Muthu;R. Velpula;N. T. Nguyen;H. Nguyen
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作者：
B. Jain;Mano Balo Sankar Muthu;R. Velpula;N. T. Nguyen;H. Nguyen
尽管AlGaN基深紫外光发光二极管(LED)已经得到了广泛的研究，但与InGaN基可见光LED相比，其量子效率和光输出功率仍然非常低。电子泄漏被认为是导致AlGaN基紫外光LED内量子效率(IQE)低的可能原因之一。在LED中集成p掺杂AlGaN电子阻挡层(EBL)或增加导带势垒高度，并迅速利用较高的Al组分量子垒(QBS)，可以在一定程度上缓解电子泄漏问题，但不是完全缓解。在此背景下，我们介绍了一种在不使用EBL的情况下缓解电子溢出的有前景的方法，即在AlGaN UV LED中使用渐变凹面量子层来代替传统的量子层。总体而言，载流子输运、限制能力和辐射复合能力都得到了显著改善。结果表明，在注入电流为60 mA时，该凹面QB LED的IQE和输出功率分别比传统LED提高了25.4%和25.6%。
Although AlGaN-based deep ultraviolet (UV) light-emitting diodes (LEDs) have been studied extensively, their quantum efficiency and optical output power still remain extremely low compared to the InGaN-based visible color LEDs. Electron leakage has been identified as one of the most possible reasons for the low internal quantum efficiency (IQE) in AlGaN based UV LEDs. The integration of a p-doped AlGaN electron blocking layer (EBL) or/and increasing the conduction band barrier heights with prompt utilization of higher Al composition quantum barriers (QBs) in the LED could mitigate the electron leakage problem to an extent, but not completely. In this context, we introduce a promising approach to alleviate the electron overflow without using EBL by utilizing graded concave QBs instead of conventional QBs in AlGaN UV LEDs. Overall, the carrier transportation, confinement capability and radiative recombination are significantly improved. As a result, the IQE, and output power of the proposed concave QB LED were enhanced by ~25.4% and ~25.6% compared to the conventional LED for emission at ~254 nm, under 60 mA injection current.