[1] S Nakamura, h M Senoh, a S Nagahama et al. InGaN/GaN/AlGaN-based laser diodes with modulation-doped strained-layer superlattices grown on an epitaxially laterally overgrown GaN substrate. Appl Phys Lett, 72, 211(1998).

[2] S Nagahama, o T Yanamoto, o M Sano et al. Ultraviolet GaN single quantum well laser diodes. Jpn J Appl Phys, 40, L785(2001).

[3] S Nagahama, o T Yanamoto, o M Sano et al. Characteristics of ultraviolet laser diodes composed of quaternary Al_xIn_yGa_(1–x–y)N. Jpn J Appl Phys,, 40, L788(2001).

[4] S Masui, a Y Matsuyama, o T Yanamoto et al. 365 nm ultraviolet laser diodes composed of quaternary AlInGaN alloy. Jpn J Appl Phys, 42, L 1318(2003).

[5] K Iida, a T Kawashima, i A Miyazaki et al. 350.9 nm UV laser diode grown on low-dislocation-density AlGaN. Jpn J Appl Phys, 43, L499(2004).

[6] H Yoshida, a Y Yamashita, a M Kuwabara et al. A 342-nm ultraviolet AlGaN multiple-quantum-well laser diode. Nat Photonics, 2, 551(2008).

[7] H Yoshida, Y Yamashita, a M Kuwabara et al. Demonstration of an ultraviolet 336 nm AlGaN multiple-quantum-well laser diode. Appl Phys Lett, 93, 241106(2008).

[8] D G Zhao, g J Yang, u Z S Liu et al. Fabrication of room temperature continuous-wave operation GaN-based ultraviolet laser diodes. J Semicond, 38, 051001(2017).

[9] D B Li, g K Jiang, n X J Sun et al. AlGaN photonics: recent advances in materials and ultraviolet devices. Adv Opt Photonics, 10, 43(2018).

[10] Z Y Zhang, o M Kushimoto, i T Sakai et al. A 271.8 nm deep-ultraviolet laser diode for room temperature operation. Appl Phys Express, 12, 124003(2019).