Design of Deep-UV Nanowire LED with Al₂O₃ Quantum Dots and Step-Graded n-Type AlInGaN Electron Blocking Layer for High Quantum Efficiency

In this paper, we have proposed a novel deep ultra-violet (DUV) AlGaN/GaN nanowire light-emitting diode (LED) with a step-graded n-type AlInGaN electron blocking layer (EBL) instead of a conventional p-type AlGaN EBL. The nanowire is designed with Al₂O₃ quantum dots (QDs) deposited all over the substrate. The proposed nanowire is designed for a ∼265 nm wavelength emission without affecting the hole injection efficiency. Due to enhanced carrier transport in the step-graded n-type EBL structure, there occurs reduced electron leakage into the p-region, superior hole activation and hole injection, improved output power and internal quantum efficiency (IQE). Moreover, this specially designed EBL reduces the quantum confined stark effect in the active region, ultimately enhancing the carrier wave functions overlap. The device structure is simulated using Atlas technology computer-aided design (TCAD). The efficiency is improved from ∼36.48% to ∼49.46% while switching from conventional p-type EBL to step-graded n-type EBL. Furthermore, our proposed structure exhibits 1.61% efficiency droop, which is significantly ∼4.8 times lower as compared to the regular structure.