[1] Kneissl M, Seong T Y, Han J et al. The emergence and prospects of deep-ultraviolet light-emitting diode technologies[J]. Nature Photonics, 13, 233-244(2019).

[2] Li J M, Liu Z Q, Wei T B et al. Development summary of semiconductor lighting in China[J]. Acta Optica Sinica, 41, 0116002(2021).

[3] Sheng B B, Wang L, Xu J T et al. Extraction of material parameters by transmission spectra of AlGaN film[J]. Acta Optica Sinica, 41, 0313001(2021).

[4] Wang J Y, Li S J, Liu T H et al. Research on all solid-state ultraviolet laser at 289.9 nm[J]. Chinese Journal of Lasers, 49, 0701001(2022).

[5] Fang M Q, Tian K K, Chu C S et al. Manipulation of Si doping concentration for modification of the electric field and carrier injection for AlGaN-based deep-ultraviolet light-emitting diodes[J]. Crystals, 8, 258(2018).

[6] Sato K, Yasue S, Ogino Y et al. Analysis of spontaneous sub-peak emission from the guide layers of ultraviolet-B laser diode structure containing composition-graded p-AlGaN cladding layer[J]. Physica Status Solidi, 217, 1900864(2020).

[7] Mi Z T, Zhao S R, Liu X H. AlGaN nanowire deep ultraviolet light emitting diodes and lasers[C](2017).

[8] Li L P, Zhang Y H, Xu S et al. On the hole injection for III-nitride based deep ultraviolet light-emitting diodes[J]. Materials, 10, 1221(2017).

[9] Chen Q, Zhang H X, Dai J N et al. Enhanced the optical power of AlGaN-based deep ultraviolet light-emitting diode by optimizing mesa sidewall angle[J]. IEEE Photonics Journal, 10, 6100807(2018).

[10] Nam K B, Li J, Nakarmi M L et al. Unique optical properties of AlGaN alloys and related ultraviolet emitters[J]. Applied Physics Letters, 84, 5264-5266(2004).

[11] Lu H M, Yu T J, Yuan G C et al. Valence subband coupling effect on polarization of spontaneous emissions from Al-rich AlGaN/AlN quantum wells[J]. Optics Express, 20, 27384-27392(2012).

[12] Sulmoni L, Mehnke F, Mogilatenko A et al. Electrical properties and microstructure formation of V/Al-based n-contacts on high Al mole fraction n-AlGaN layers[J]. Photonics Research, 8, 1381-1387(2020).

[13] Kwon M R, Park T H, Lee T H et al. Improving the performance of AlGaN-based deep-ultraviolet light-emitting diodes using electron blocking layer with a heart-shaped graded Al composition[J]. Superlattices and Microstructures, 116, 215-220(2018).

[14] Wang L Y, He W, Zheng T et al. Enhanced optical performance of AlGaN-based deep-ultraviolet light-emitting diode with m-shaped hole blocking layer and w-shaped electron blocking layer[J]. Superlattices and Microstructures, 133, 106188(2019).

[15] Omori T, Ishizuka S, Tanaka S et al. Internal loss of AlGaN-based ultraviolet-B band laser diodes with p-type AlGaN cladding layer using polarization doping[J]. Applied Physics Express, 13, 071008(2020).

[16] Zhang Y, Kao T T, Liu J P et al. Effects of a step-graded AlxGa1-xN electron blocking layer in InGaN-based laser diodes[J]. Journal of Applied Physics, 109, 083115(2011).

[17] Long H L, Wu F, Zhang J et al. Anisotropic optical polarization dependence on internal strain in AlGaN epilayer grown on AlxGa1-xN templates[J]. Journal of Physics D: Applied Physics, 49, 415103(2016).

[18] Long H L, Wang S, Dai J N et al. Internal strain induced significant enhancement of deep ultraviolet light extraction efficiency for AlGaN multiple quantum wells grown by MOCVD[J]. Optics Express, 26, 680-686(2018).

[19] Kuhn C, Martens M, Mehnke F et al. Influence of waveguide strain and surface morphology on AlGaN-based deep UV laser characteristics[J]. Journal of Physics D: Applied Physics, 51, 415101(2018).

[20] Xing Z Q, Zhou Y J, Chen X et al. Increased radiative recombination of AlGaN-based deep ultraviolet laser diodes with convex quantum wells[J]. Optoelectronics Letters, 16, 87-91(2020).

[21] Chang Y D, Wang Z F et al. Waveguide optimization and efficiency characteristic analysis of 808 nm laser diodes[J]. Chinese Journal of Luminescence, 42, 1040-1048(2021).

[22] Chen H Y, Liu D Y, Li J C et al. High Al group Ⅲ nitride structural materials and their application in deep ultraviolet LED[J]. Progress in Physics, 33, 43-56(2013).

[23] Liang F, Zhao D G, Jiang D S et al. Suppression of optical field leakage in GaN-based green laser diode using graded-indium n-InxGa1-xN lower waveguide[J]. Superlattices and Microstructures, 132, 106153(2019).

[24] Kanskar M, Earles T, Goodnough T et al. High-power conversion efficiency Al-free diode lasers for pumping high-power solid-state laser systems[J]. Proceedings of SPIE, 5738, 47-56(2005).

[25] Botez D, Mawst L J, Bhattacharya A et al. 66% CW wallplug efficiency from Al-free 0.98 μm-emitting diode lasers[J]. Electronics Letters, 32, 2012-2013(1996).

[26] Golikova E, Gorbylev V, Davidyuk N et al. Separately bounded InGaAsP high-power laser heterostructures obtained by VPE of organometallic compounds[J]. Technical Physics Letters, 26, 225-227(2000).

[27] Hou Y F, Zhao D G, Liang F et al. Characteristics of InGaN-based green laser diodes with additional InGaN hole reservoir layer[J]. Vacuum, 186, 110049(2021).

[28] Prasad S, Mondal R K, Chatterjee V et al. Double-side step-graded AlGaN electron blocking layer for nearly droop-free GaN-based blue LEDs[J]. Superlattices and Microstructures, 132, 106167(2019).

[29] Xing Z Q, Zhou Y J, Liu Y H et al. Reduction of electron leakage of AlGaN-based deep ultraviolet laser diodes using an inverse-trapezoidal electron blocking layer[J]. Chinese Physics Letters, 37, 027302(2020).