The optoelectronic characteristics of AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) with quaternary last quantum barrier (QLQB) and step-graded electron blocking layer (EBL) are investigated numerically. The results show that the internal quantum efficiency (IQE) and radiative recombination rate are remarkably improved with AlInGaN step-graded EBL and QLQB as compared to conventional or ternary AlGaN EBL and last quantum barrier (LQB). This significant improvement is assigned to the optimal recombination of electron–hole pairs in the multiple quantum wells (MQWs). It is due to the decrease in strain and lattice mismatch between the epi-layers which alleviates the effective potential barrier height of the conduction band and suppressed the electron leakage without affecting the holes transportation to the active region. Moreover, to figure out quantitatively, the electron and hole quantity increased by ~ 25% and ~ 15%, respectively. Additionally, the IQE and radiative recombination rate are enhanced by 48% and 55%, respectively, as compared to conventional LED. So, we believe that our proposed structure is not only a feasible approach for achieving highly efficient DUV LEDs, but the device physics presented in this study establishes a fruitful understanding of III nitride-based optoelectronic devices.

数值研究了具有四元末量子势垒（QLQB）和阶梯电子阻挡层（EBL）的AlGaN基深紫外发光二极管（DUV LED）的光电特性。结果表明，与传统或三元 AlGaN EBL 和最后量子势垒 (LQB) 相比，AlInGaN 阶梯梯度 EBL 和 QLQB 的内量子效率 (IQE) 和辐射复合率显着提高。这一显着改进归因于多量子阱（MQW）中电子-空穴对的最佳复合。这是由于外延层之间的应变和晶格失配的减少，这减轻了导带的有效势垒高度并抑制了电子泄漏而不影响空穴向有源区的传输。而且，定量计算，电子和空穴数量分别增加了~25%和~15%。此外，与传统 LED 相比，IQE 和辐射复合率分别提高了 48% 和 55%。因此，我们相信我们提出的结构不仅是实现高效 DUV LED 的可行方法，而且本研究中提出的器件物理特性为基于 III 族氮化物的光电器件建立了富有成果的理解。