Last-Quantum-Barrier-Free AlGaN Deep Ultraviolet LEDs With Boosted Efficiency

AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) still suffer from poor quantum efficiency and low optical power. Herein, we propose a 273-nm DUV LED architecture by removing the last quantum barrier (LQB), which bridges the active region and hole injection region that significantly boosts the overall performance of the device. The light output power (LOP) can be remarkably boosted by 147% at an injection current of 65 A/cm2 in comparison with a conventional LED with LQB, attributing to the effective improvement of electron-blocking capabilities and hole injection efficiency. Additionally, due to the removal of LQB, we found that the thickness of the last quantum well (LQW) has to be optimized to lower electron leakage, which further enhances the efficiency of the device. Such LQB-free DUV LED provides an alternate route to the development of efficient DUV devices.