AlGaN-Based Deep-Ultraviolet Laser Diodes with Quaternary AlInGaN Last Quantum Barrier

We propose the quaternary AlInGaN last quantum barrier (LQB) structure to improve the performance of deep-ultraviolet (DUV) laser diodes (LDs). Here, we investigate three LQB structures – Al 0 . 63 In 0 . 03 Ga 0 . 34 N LQB, Al 0 . 65 In 0 . 03 Ga 0 . 32 N LQ band, and Al 0 . 68 In 0 . 03 Ga 0 . 29 N LQB. We find that the Al 0 . 68 In 0 . 03 Ga 0 . 29 N LQB structure significantly reduces the electron leakage in the p -region, improves the carrier injection efficiency in the active region, and increases the stimulated radiation recombination rate of the DUV LDs. The simulation results indicate that the threshold current and threshold voltage decrease from 50.93 mA and 4.70 V for the Al 0 . 63 In 0 . 03 Ga 0 . 34 N LQB structure to 42.47 mA and 4.63 V for the Al 0 . 68 In 0 . 03 Ga 0 . 29 N LQB structure, respectively. At an injection current of 100 mA, the slope efficiency increases to 1.12 W/A. Compared with the conventional ternary AlGaN LQB structure, the quaternary AlInGaN LQB structure significantly improves the performance of the DUV LDs, which is crucial for the development of the DUV LDs.