[1] M. A. Wurtele, T. Kolbe, M. Lipsz, A. Kulberg, M. Weyers, M. Kneissl, M. Jekel. Application of GaN-based ultraviolet-C light emitting diodes—UV LEDs—for water disinfection. Water Res., 45, 1481-1489(2011).

[2] A. J. Hopkins, J. L. Cooper, L. T. M. Profeta, A. R. Ford. Portable deep-ultraviolet (DUV) Raman for standoff detection. Appl. Spectrosc., 70, 861-873(2016).

[3] S. J. Choi, J. H. Kim, H. H. Lee. Deep-UV curing of poly(4-vinyl phenol) gate dielectric for hysteresis-free organic thin-film transistors. IEEE Electron Device Lett., 30, 454-456(2009).

[4] J. Rass, T. Kolbe, N. L. Ploch, T. Wernicke, F. Mehnke, C. Kuhn, J. Enslin, M. Guttmann, C. Reich, A. Mogilatenko, J. Glaab, C. Stoelmacker, M. Lapeyrade, S. Einfeldt, M. Weyers, M. Kneissl. High power UV-B LEDs with long lifetime. Proc. SPIE, 9363, 93631K(2015).

[5] H. Y. Ryu, I. G. Choi, H. S. Choi, J. I. Shim. Investigation of light extraction efficiency in AlGaN deep-ultraviolet light-emitting diodes. Appl. Phys. Express, 6, 062101(2013).

[6] H. Hirayama, T. Takano, J. Sakai, T. Mino, K. Tsubaki, N. Maeda, M. Jo, Y. Kanazawa, I. Ohshima, T. Matsumoto, N. Kamata. Realization of over 10% EQE AlGaN deep-UV LED by using transparent p-AlGaN contact layer. 2016 International Semiconductor Laser Conference, 1-2(2016).

[7] R. G. Banal, M. Funato, Y. Kawakami. Optical anisotropy in [0001]-oriented Al_xGa_1-xN/AlN quantum wells (x > 0.69). Phys. Rev. B, 79, 121308(2009).

[8] X. J. Chen, C. Ji, Y. Xiang, X. N. Kang, B. Shen, T. J. Yu. Angular distribution of polarized light and its effect on light extraction efficiency in AlGaN deep-ultraviolet light-emitting diodes. Opt. Express, 24, A935-A942(2016).

[9] J. Zhang, H. P. Zhao, N. Tansu. Effect of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content AlGaN quantum well lasers. Appl. Phys. Lett., 97, 111105(2010).

[10] M. Djavid, Z. T. Mi. Enhancing the light extraction efficiency of AlGaN deep ultraviolet light emitting diodes by using nanowire structures. Appl. Phys. Lett., 108, 051102(2016).

[11] S. Zhao, S. M. Sadaf, S. Vanka, Y. Wang, R. Rashid, Z. Mi. Sub-milliwatt AlGaN nanowire tunnel junction deep ultraviolet light emitting diodes on silicon operating at 242  nm. Appl. Phys. Lett., 109, 201106(2016).

[12] T. F. Kent, S. D. Carnevale, A. T. M. Sarwar, P. J. Phillips, R. F. Klie, R. C. Myers. Deep ultraviolet emitting polarization induced nanowire light emitting diodes with Al_xGa_1-xN active regions. Nanotechnology, 25, 455201(2014).

[13] S. M. Sadaf, S. Zhao, Y. Wu, Y. H. Ra, X. Liu, S. Vanka, Z. Mi. An AlGaN core-shell tunnel junction nanowire light-emitting diode operating in the ultraviolet-C band. Nano Lett., 17, 1212-1218(2017).

[14] M. Djavid, D. D. Choudhary, M. Rajan Philip, T. H. Q. Bui, O. Akinnuoye, T. T. Pham, H. P. T. Nguyen. Effects of optical absorption in deep ultraviolet nanowire light-emitting diodes. Photon. Nanostr. Fundam. Appl., 28, 106-110(2018).

[15] J. J. Wierer, A. David, M. M. Megens. III-nitride photonic-crystal light-emitting diodes with high extraction efficiency. Nat. Photonics, 3, 163-169(2009).

[16] A. A. Erchak, D. J. Ripin, S. Fan, P. Rakich, J. D. Joannopoulos, E. P. Ippen, G. S. Petrich, L. A. Kolodziejski. Enhanced coupling to vertical radiation using a two-dimensional photonic crystal in a semiconductor light-emitting diode. Appl. Phys. Lett., 78, 563-565(2001).

[17] C. Wiesmann, K. Bergenek, N. Linder, U. T. Schwarz. Photonic crystal LEDs—designing light extraction. Laser Photon. Rev., 3, 262-286(2009).

[18] E. M. Purcell. Spontaneous emission probabilities at radio frequencies. Phys. Rev., 69, 681(1946).

[19] M. Fujita, S. Takahashi, Y. Tanaka, T. Asano, S. Noda. Simultaneous inhibition and redistribution of spontaneous light emission in photonic crystals. Science, 308, 1296-1298(2005).

[20] H. D. Sun, A. Piquette, M. Raukas, T. D. Moustakas. Enhancement of yellow light extraction efficiency of Y₃Al₅O₁₂:Ce³⁺ ceramic converters using a 2-D TiO₂ hexagonal-lattice nanocylinder photonic crystal layer. IEEE Photon. J., 8, 4500310(2016).

[21] A. David, T. Fujii, R. Sharma, K. McGroddy, S. Nakamura, S. P. DenBaars, E. L. Hu, C. Weisbuch, H. Benisty. Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution. Appl. Phys. Lett., 88, 061124(2006).

[22] B. Janjua, H. Sun, C. Zhao, D. H. Anjum, F. Wu, A. A. Alhamoud, X. Li, A. M. Albadri, A. Y. Alyamani, M. M. El-Desouki, T. K. Ng, B. S. Ooi. Self-planarized quantum-disks-in-nanowires ultraviolet-B emitters utilizing pendeo-epitaxy. Nanoscale, 9, 7805-7813(2017).

[23] S. Zhao, S. Y. Woo, S. M. Sadaf, Y. Wu, A. Pofelski, D. A. Laleyan, R. T. Rashid, Y. Wang, G. A. Botton, Z. Mi. Molecular beam epitaxy growth of Al-rich AlGaN nanowires for deep ultraviolet optoelectronics. APL Mater., 4, 086115(2016).

[24] K. H. Li, X. Liu, Q. Wang, S. Zhao, Z. Mi. Ultralow-threshold electrically injected AlGaN nanowire ultraviolet lasers on Si operating at low temperature. Nat. Nanotechnol., 10, 140-144(2015).

[25] Q. Y. Yue, K. Li, F. M. Kong, J. Zhao, W. Li. Analysis on the light extraction efficiency of GaN-based nanowires light-emitting diodes. IEEE J. Quantum Electron., 49, 697-704(2013).

[26] B. Janjua, H. D. Sun, C. Zhao, D. H. Anjum, D. Priante, A. A. Alhamoud, F. Wu, X. H. Li, A. M. Albadri, A. Y. Alyamani, M. M. El-Desouki, T. K. Ng, B. S. Ooi. Droop-free Al_xGa_1−xN/Al_yGa_1−yN quantum-disks-in-nanowires ultraviolet LED emitting at 337  nm on metal/silicon substrates. Opt. Express, 25, 1381-1390(2017).

[27] D. E. Aspnes, A. A. Studna. Dielectric functions and optical-parameters of Si, Ge, GaP, GaAs, GaSb, InP, InAs, and InSb from 1.5 to 6.0  eV. Phys. Rev. B, 27, 985-1009(1983).

[28] S. Adachi. Optical Constants of Crystalline and Amorphous Semiconductors: Numerical Data and Graphical Information(1999).

[29] S. Zhao, X. Liu, S. Y. Woo, J. Kang, G. A. Botton, Z. Mi. An electrically injected AlGaN nanowire laser operating in the ultraviolet-C band. Appl. Phys. Lett., 107, 043101(2015).

[30] S. D. Carnevale, J. Yang, P. J. Phillips, M. J. Mills, R. C. Myers. Three-dimensional GaN/AIN nanowire heterostructures by separating nucleation and growth processes. Nano Lett., 11, 866-871(2011).

[31] S. Fernandez-Garrido, X. Kong, T. Gotschke, R. Calarco, L. Geelhaar, A. Trampert, O. Brandt. Spontaneous nucleation and growth of GaN nanowires: the fundamental role of crystal polarity. Nano Lett., 12, 6119-6125(2012).

[32] A. Pierret, C. Bougerol, S. Murcia-Mascaros, A. Cros, H. Renevier, B. Gayral, B. Daudin. Growth, structural and optical properties of AlGaN nanowires in the whole composition range. Nanotechnology, 24, 115704(2013).

[33] S. G. Johnson, J. D. Joannopoulos. Block-iterative frequency-domain methods for Maxwell’s equations in a planewave basis. Opt. Express, 8, 173-190(2001).

[34] T. Kolbe, A. Knauer, C. Chua, Z. H. Yang, S. Einfeldt, P. Vogt, N. M. Johnson, M. Weyers, M. Kneissl. Optical polarization characteristics of ultraviolet (In)(Al)GaN multiple quantum well light emitting diodes. Appl. Phys. Lett., 97, 171105(2010).

[35] S. G. Johnson, S. H. Fan, P. R. Villeneuve, J. D. Joannopoulos, L. A. Kolodziejski. Guided modes in photonic crystal slabs. Phys. Rev. B, 60, 5751-5758(1999).

[36] D. R. Solli, J. M. Hickmann. Study of the properties of 2D photonic crystal structures as a function of the air-filling fraction and refractive index contrast. Opt. Mater., 33, 523-526(2011).

[37] P. F. Zhu, N. Tansu. Effect of packing density and packing geometry on light extraction of III-nitride light-emitting diodes with microsphere arrays. Photon. Res., 3, 184-191(2015).

[38] Y. Tanaka, T. Asano, Y. Akahane, B. S. Song, S. Noda. Theoretical investigation of a two-dimensional photonic crystal slab with truncated cone air holes. Appl. Phys. Lett., 82, 1661-1663(2003).

[39] J. W. Kim, J. H. Jang, M. C. Oh, J. W. Shin, D. H. Cho, J. H. Moon, J. I. Lee. FDTD analysis of the light extraction efficiency of OLEDs with a random scattering layer. Opt. Express, 22, 498-507(2014).