Jamil Tariq, Usman Muhammad, Malik Shahzeb, Jamal Habibullah
Faculty of Engineering Sciences, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, 23460 Khyber Pakhtunkhwa Pakistan.
Appl Phys A Mater Sci Process. 2021;127(5):397. doi: 10.1007/s00339-021-04559-w. Epub 2021 May 4.
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.
对具有四元末次量子势垒（QLQB）和阶梯渐变电子阻挡层（EBL）的基于AlGaN的深紫外发光二极管（DUV LED）的光电特性进行了数值研究。结果表明，与传统的或三元AlGaN EBL及末次量子势垒（LQB）相比，采用AlInGaN阶梯渐变EBL和QLQB时，内部量子效率（IQE）和辐射复合率显著提高。这种显著的提高归因于多量子阱（MQW）中电子 - 空穴对的最佳复合。这是由于外延层之间应变和晶格失配的降低，减轻了导带的有效势垒高度并抑制了电子泄漏，同时不影响空穴向有源区的传输。此外，为了定量分析，电子和空穴数量分别增加了约25%和约15%。另外，与传统LED相比，IQE和辐射复合率分别提高了48%和55%。所以，我们认为我们提出的结构不仅是实现高效DUV LED的一种可行方法，而且本研究中呈现的器件物理对基于III族氮化物的光电器件有了富有成效的理解。
