Overcoming Asymmetric Carrier Injection in III-Nitride Light-Emitting Diodes through Defect Engineering

The rapid advancements in the semiconductor industry are often accompanied by a breakthrough in defect engineering. While defects usually hinder device performance, they can also offer new opportunities for manipulating semiconductor properties. In this Letter, we present an effective approach to solving the long-standing asymmetric injection of carriers problem in LEDs by introducing nitrogen vacancies (V_{N}) at the GaN/AlN quantum well (QW) interface. The V_{N} states function as "steps" as well as sources of perturbation potential to improve the electron relaxation to the bottom of the conduction band through the electron-phonon (el-ph) coupling. The electron relaxation time (τ_{e}), initially as long as 8.61 ps, was reduced to 0.15 ps, comparable to the τ_{h} (0.12 ps). Our work not only resolves a persistent bottleneck in GaN-based light sources but also offers a new perspective on utilizing defects to engineer carrier relaxation.