Performance Improvement of AlGaN-Based Deep Ultraviolet Light-Emitting Diodes With Step-Like Quantum Barriers

AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) still confront many challenges, which is partially limited by the poor carrier injection in the active region. Although incorporating a high Al-composition quantum barrier (QB) may boost carrier confinement capability, it will aggravate the quantum confined Stark effect (QCSE) and thus deteriorate the optical performance. In this article, a DUV LED structure with step-like QBs has been proposed and carefully investigated. This unique QB structure suppresses the electron overflow into the p-side of the device and benefits the hole injection efficiency simultaneously, thereby promoting the radiative recombination rate in the active region. As a result, the internal quantum efficiency (IQE) and light output power (LOP) of the DUV LED with step-like QBs are significantly improved with an enhancement factor of 40% under 60 mA current injection. Therefore, our step-like QB design provides a feasible approach to the enhancement of the optical performance of DUV LEDs.