Efficiency improvements in AlGaN-based deep-ultraviolet light-emitting diodes with p-doped graded AlInGaN last quantum barrier

This paper presents an analytical study on the luminescence characteristics of the p‑doped graded AlInGaN last quantum barrier (Structure C) in deep-ultraviolet light-emitting diodes (LEDs). Compared to the conventional structure, the results indicate that Structure C significantly enhances the effective barrier height for electrons from 426 to 713 meV, while reducing the effective barrier height for holes from 418 to 371 meV. The internal quantum efficiency increases from 62.5% to 95.4%, and the light output power is enhanced from 97 to 430 mW. Additionally, the slope efficiency rises from 0.9 to 4.3 W/A. Simulation results demonstrate that Structure C achieves the highest carrier concentration in the active region, although the radiative recombination rate in the last quantum well is lower than that of the other structures. These findings suggest that the p‑doped graded AlInGaN LQB represents an effective approach for achieving highly efficient deep-ultraviolet light-emitting diodes.