[1] NAGASAWA Y, HIRANO A. A review of AlGaN-based deep-ultraviolet light-emitting diodes on sapphire[J]. Applied Sciences, 2018, 8(8): 1264. [2] LI D B, JIANG K, SUN X J, et al. AlGaN photonics: recent advances in materials and ultraviolet devices[J]. Advances in Optics and Photonics, 2018, 10(1): 43-110. [3] CHEN Y X, BEN J W, XU F J, et al. Review on the progress of AlGaN-based ultraviolet light-emitting diodes[J]. Fundamental Research, 2021, 1(6): 717-734. [4] LI J C, GAO N, CAI D J, et al. Multiple fields manipulation on nitride material structures in ultraviolet light-emitting diodes[J]. Light: Science & Applications, 2021, 10: 129. [5] TAKANO T, MINO T, JUN S K, et al. Deep-ultraviolet light-emitting diodes with external quantum efficiency higher than 20% at 275 nm achieved by improving light-extraction efficiency[J]. Applied Physics Express, 2017, 10(3): 031002. [6] LU H M, CHEN M R, WANG H, et al. Joint evaluation of internal quantum efficiency and light extraction efficiency for AlGaN-based deep ultraviolet LEDs considering optical polarization properties[J]. Journal of Applied Physics, 2020, 128(12): 125703. [7] CHOI Y H, RYU G H, RYU H Y. Evaluation of the temperature-dependent internal quantum efficiency and the light-extraction efficiency in a GaN-based blue light-emitting diode by using a rate equation model[J]. Journal of the Korean Physical Society, 2016, 69(8): 1286-1289. [8] YOSHIKAWA A, CHE S B, YAMAGUCHI W, et al. Proposal and achievement of novel structure InN/GaN multiple quantum wells consisting of 1 ML and fractional monolayer InN wells inserted in GaN matrix[J]. Applied Physics Letters, 2007, 90(7): 073101. [9] SHIH Y H, CHANG J Y, SHEU J K, et al. Design of hole-blocking and electron-blocking layers in AlxGa1-xN-based UV light-emitting diodes[J]. IEEE Transactions on Electron Devices, 2016, 63(3): 1141-1147. [10] WU F, SUN H D, AJIA I A, et al. Significant internal quantum efficiency enhancement of GaN/AlGaN multiple quantum wells emitting at ~350 nm via step quantum well structure design[J]. Journal of Physics D: Applied Physics, 2017, 50(24): 245101. [11] HAUGHN C R, RUPPER G, WUNDERER T, et al. Highly radiative nature of ultra-thin c-plane Al-rich AlGaN/AlN quantum wells for deep ultraviolet emitters[J]. Applied Physics Letters, 2019, 114(10): 102101. [12] ZEIMER U, JESCHKE J, MOGILATENKO A, et al. Spatial inhomogeneities in AlxGa1-xN quantum wells induced by the surface morphology of AlN/sapphire templates[J]. Semiconductor Science and Technology, 2015, 30(11): 114008. [13] BRYAN I, BRYAN Z, MITA S, et al. Surface kinetics in AlN growth: a universal model for the control of surface morphology in III-nitrides[J]. Journal of Crystal Growth, 2016, 438: 81-89. [14] BRYAN I, BRYAN Z, MITA S, et al. The role of surface kinetics on composition and quality of AlGaN[J]. Journal of Crystal Growth, 2016, 451: 65-71. [15] HOU M J, QIN Z X, ZHANG L S, et al. Excitonic localization at macrostep edges in AlGaN/AlGaN multiple quantum wells[J]. Superlattices and Microstructures, 2017, 104: 397-401. [16] SUN Y H, XU F J, XIE N, et al. Controlled bunching approach for achieving high efficiency active region in AlGaN-based deep ultraviolet light-emitting devices with dual-band emission[J]. Applied Physics Letters, 2020, 116(21): 212102. [17] SUN H D, MITRA S, SUBEDI R C, et al. Unambiguously enhanced ultraviolet luminescence of AlGaN wavy quantum well structures grown on large misoriented sapphire substrate[J]. Advanced Functional Materials, 2019, 29(48): 1905445. [18] ALBRECHT M, CREMADES A, KRINKE J, et al. Carrier recombination at screw dislocations in n-type AlGaN layers[J]. Physica Status Solidi (b), 1999, 216(1): 409-414. [19] WONG Y Y, CHANG E Y, YANG T H, et al. The roles of threading dislocations on electrical properties of AlGaN/GaN heterostructure grown by MBE[J]. Journal of the Electrochemical Society, 2010, 157(7): H746. [20] REMESH N, MOHAN N, KUMAR S, et al. Vertical current transport in AlGaN/GaN HEMTs on silicon: experimental investigation and analytical model[J]. IEEE Transactions on Electron Devices, 2019, 66(1): 613-618. [21] SHEN X Q, OKUMURA H, MATSUHATA H. Studies of the annihilation mechanism of threading dislocation in AlN films grown on vicinal sapphire (0001) substrates using transmission electron microscopy[J]. Applied Physics Letters, 2005, 87(10): 101910. [22] SHEN X Q, MATSUHATA H, OKUMURA H. Reduction of the threading dislocation density in GaN films grown on vicinal sapphire (0001) substrates[J]. Applied Physics Letters, 2005, 86(2): 021912. [23] SHEN X Q, MATSUHATA H, IDE T, et al. Direct measurement of lateral macrostep velocity on an AlN vicinal surface by transmission electron microscopy[J]. Journal of Applied Physics, 2012, 111(10): 103529. [24] MIYAKE H, LIN C H, TOKORO K, et al. Preparation of high-quality AlN on sapphire by high-temperature face-to-face annealing[J]. Journal of Crystal Growth, 2016, 456: 155-159. [25] WANG M X, XU F J, WANG J M, et al. The sapphire substrate pretreatment effects on high-temperature annealed AlN templates in deep ultraviolet light emitting diodes[J]. CrystEngComm, 2019, 21(31): 4632-4636. [26] SUSILO N, HAGEDORN S, JAEGER D, et al. AlGaN-based deep UV LEDs grown on sputtered and high temperature annealed AlN/sapphire[J]. Applied Physics Letters, 2018, 112(4): 041110. [27] BEN J W, SUN X J, JIA Y P, et al. Defect evolution in AlN templates on PVD-AlN/sapphire substrates by thermal annealing[J]. CrystEngComm, 2018, 20(32): 4623-4629. [28] FAN Z Y, RONG G, NEWMAN N, et al. Defect annihilation in AlN thin films by ultrahigh temperature processing[J]. Applied Physics Letters, 2000, 76(14): 1839-1841. [29] XIONG J J, TANG J J, LIANG T, et al. Characterization of crystal lattice constant and dislocation density of crack-free GaN films grown on Si(111)[J]. Applied Surface Science, 2010, 257(4): 1161-1165. [30] CHIERCHIA R, BÖTTCHER T, HEINKE H, et al. Microstructure of heteroepitaxial GaN revealed by X-ray diffraction[J]. Journal of Applied Physics, 2003, 93(11): 8918-8925. [31] KUBALL M, HAYES J M, PRINS A D, et al. Raman scattering studies on single-crystalline bulk AlN under high pressures[J]. Applied Physics Letters, 2001, 78(6): 724-726. [32] WANG M X, XU F J, XIE N, et al. High-temperature annealing induced evolution of strain in AlN epitaxial films grown on sapphire substrates[J]. Applied Physics Letters, 2019, 114(11): 11210 |