[2] [2] Blasing J, Reiher A, Dadgar A, et al. The origin of stress reduction by lowtemperature AlN interlayers[J]. Appl. Phys. Lett., 2002, 81(15): 27222724.

[3] [3] Feltin Eric, Beaumont B, Laügt M, et al. Stress control in GaN grown on silicon (111) by metalorganic vapor phase epitaxy[J]. Appl. Phys. Lett., 2001, 79(20): 32303232.

[4] [4] Demir I, Li H, Robin Y, et al. Sandwich method to grow high quality AlN by MOCVD[J]. J. of Physics D: Appl. Phys., 2022, 51(8): 085104.

[5] [5] Zhang X, Xu F J, Wang J M, et al. Epitaxial growth of AlN films on sapphire via a multilayer structure adopting a low and high temperature alternation technique[J]. Cryst. Eng. Comm., 2015, 17: 74967499.

[6] [6] Cicek E, McClintock R, Cho C Y, et al. AlxGa1-xNbased solarblind ultraviolet photodetector based on lateral epitaxial overgrowth of AlN on Si substrate[J]. Appl. Phys. Lett., 2013, 103: 181113.

[7] [7] Cicek E, McClintock R, Vashaei Z, et al. Crackfree AlGaN for solarblind focal plane arrays through reduced area epitaxy[J]. Appl. Phys. Lett., 2013, 102: 051102.

[8] [8] Chen Y Y, Chen Z Z, Jiang S X, et al. Fabrication of nanopatterned sapphire substrates by combining nanoimprint lithography with edge effects[J]. Cry. Steng. Comm., 2019, 21(11): 1794.

[9] [9] Adivarahan V, Simin G, Tamulaitis G, et al. Indiumsilicon codoping of highaluminumcontent AlGaN for solar blind photodetectors[J]. Appl. Phys. Lett., 2001, 79(12): 19031905.

[10] [10] Cantu P, Keller S, Mishra U K, et al. Metalorganic chemical vapor deposition of highly conductive Al0.65Ga0.35N films[J]. Appl. Phys. Lett., 2013, 82(21): 36833685.

[11] [11] Demir I, Koak Y, Kasapogˇ lu A E，et al. AlGaN/AlN MOVPE heteroepitaxy: pulsed codoping SiH4 and TMIn[J]. Semiconductor Science and Technol., 2019, 34: 075028.

[12] [12] Huang C P, Gupta K, Wang C H, et al. Highquality AlN grown with a single substrate temperature below 1200℃[J]. Scientific Reports, 2017, 7: 7135.

[13] [13] Erdem C, Zahra V, Edward KKH, et al. AlxGa1-xNbased deepultraviolet 320×256 focal plane array[J]. Opt. Lett., 2012, l37(5): 896898.

[14] [14] Wang J M, Xu F J, He C G, et al. High quality AlN epilayers grown on nitrided sapphire by metal organic chemical vapor deposition[J]. Scientific Reports, 2017, 7: 42747.

[15] [15] Raghothamachar B, Dalmau R, Moody B, et al. Low defect density bulk AlN substrates for high performance electronics and optoelectronics[J]. Materials Science Forum, 2012, 717720: 12871290.

[16] [16] Gautam L, Lee J, Brown G, et al. Low dark current deep UV AlGaN photodetectors on AlN substrate[J]. IEEE J. of Quantum Electronics, 2022, 58(3): 4000205.

[17] [17] Sood A K, Zeller J W, Puri Y R, et al. Development of high gain GaN/AlGaN avalanche photodiode arrays for UV detection and imaging applications[J]. Inter. J. of Engineering Research and Technol., 2017, 10(2): 129150.

[18] [18] Yoshinao K, Nao T, Ken G, et al. Mass production of AlN substrates by high speed homoepitaxial growth[J]. SPIE, 2021, 11706: 117060M.

[19] [19] Bayram C, Pau J L, McClintock R, et al. Deltadoping optimization for high quality ptype GaN[J]. J. of Appl. Phys., 2008, 104(8): 083512.

[20] [20] Kalra A, Rathkanthiwar S, Muralidharan R, et al. Polarizationgraded AlGaN solarblind pin detector with 92% zerobias external quantum efficiency[J]. IEEE Photon. Technol. Lett., 2019, 31(15): 12371240.

[21] [21] Dalmaua R, Moody B. Polarizationinduced doping in graded AlGaN epilayers grown on AlN single crystal substrates[J]. ECS Transactions, 2018, 86(12): 3140.

[22] [22] Cheng B, Choi S, Northrup J E, et al. Enhanced vertical and lateral hole transport in high aluminumcontaining AlGaN for deep ultraviolet light emitters[J]. Appl. Phys. Lett., 2013, 102: 231106.

[23] [23] Zheng T C, Lin W, Liu R, et al. Improved ptype conductivity in Alrich AlGaN using multidimensional Mgdoped superlattices[J]. Scientific Reports, 2016, 6: 21897.

[24] [24] Chen Y D, Wu H L, Han E Z, et al. High hole concentration in ptype AlGaN by indiumsurfactantassisted Mgdelta doping[J]. Appl. Phys. Lett., 2015, 106: 162102.

[25] [25] Luo W K, Liu B, Li Z H, et al. Enhanced ptype conduction in AlGaN grown by metalsource flowrate modulation epitaxy[J]. Appl. Phys. Lett., 2018, 113: 072107.

[26] [26] Jiang K, Sun X J, Shi Z M, et al. Quantum engineering of nonequilibrium efficient pdoping in ultrawide bandgap nitrides[J]. Science & Applications, 2021, 10: 69.

[27] [27] Liang Y, Ma M G, Zhong X P, et al. Multilayered PdTe2/GaN heterostructures for visibleblind deepultraviolet photodetection[J]. IEEE Electron Device Lett., 2021, 42(8): 11921195.

[28] [28] Zhao Z Q, Chu C H, Zhang G, et al. Tuning the plasmonic resonance peak for Al nanorods on AlGaN layer to deep ultraviolet band[J]. IEEE Photonics J., 2021, 13(5): 4800107.

[29] [29] Lu N Y, Gu Y, Weng Y Y, et al. Localized surface plasmon enhanced photoresponse of AlGaN MSM solarblind ultraviolet photodetectors[J]. Materials Research Express, 2019, 6(9): 095033.

[30] [30] Zhang W, Xu J, Ye W, et al. Plasmonic enhanced AlGaN solarblind ultraviolet photodetectors with sizetunable Al nanoparticles[J]. Adv. Photonics, 2015: IM2B.8.

[31] [31] So H Y, Lim J W, Suria A J, et al. Highly antireflective AlGaN/GaN ultraviolet photodetectors using ZnO nanorod arrays on inverted pyramidal surfaces[J]. Appl. Surface Science, 2017, 409: 9196.

[32] [32] Cicek E, McClintock R, Cho C Y, et al. AlxGa1-xNbased backilluminated solarblind photodetectors with external quantum efficiency of 89%[J]. Appl. Phys. Lett., 2013, 103: 191108.

[34] [34] Reverchon J L, Bansropun S, Truffer J P, et al. Performances of AlGaN based focal plane arrays from 10nm to 200nm[J]. SPIE, 2010, 7691: 769109.

[35] [35] Malinowski P E, Duboz J Y, Moor P D, et al. 10μm pixeltopixel pitch hybrid backside illuminated AlGaNonSi imagers for solar blind EUV radiation detection[C]// 2010 Inter. Electron Devices Meeting, 2010: 14.5.1.

[36] [36] Malinowski P E, Duboz J, De Moor P, et al. AlGaNonSibased 10μm pixeltopixel pitch hybrid imagers for the EUV range[J]. IEEE Electron Device Lett., 2011, 32(11): 15611563.

[37] [37] McClintock R, Razeghi M. Growth of AlGaN on silicon substrates: a novel way to make backilluminated ultraviolet photodetectors[J]. Proc. of SPIE, 2015, 9555: 95550U.

[38] [38] Shao G Z, Chen D J, et al. Highgain AlGaN solarblind avalanche photodiodes[J]. IEEE Electron Device Letters, 2014, 35(3): 372374.

[39] [39] Kim J, Ji M H, Detchprohm T, et al. AlxGa1-xN ultraviolet avalanche photodiodes with avalanche gain greater than 105[J]. IEEE Photon. Technol. Lett., 2015, 27(6): 642645.

[40] [40] Cicek E, Vashaei Z, et al. Geigermode operation of ultraviolet avalanche photodiodes grown on sapphire and freestanding GaN substrates[J]. Appl. Phys. Lett., 2010, 96: 261107.

[41] [41] Ji M H, Kim J, Detchprohm T, et al. Uniform and reliable GaN pin ultraviolet avalanche photodiode arrays[J]. IEEE Photon. Technol. Lett., 2016, 28(19): 20152018.

[42] [42] Sood, Ashok, Zeller, et al. Development of highperformance detector technology for UV and IR applications[J]. Proc. of SPIE, 2019, 11151: 1115113.

[43] [43] Ji M H, Jeong H, Noodeh M B, et al. Demonstration of uniform and reliable GaN pipin separateabsorption and multiplication ultraviolet avalanche photodiode arrays with large detection area[J]. Proc. of SPIE, 2019, 10918: 1091814.

[44] [44] Reddy P, Breckenridge M H, Guo Q, et al. High gain, large area, and solar blind avalanche photodiodes based on Alrich AlGaN grown on AlN substrates[J]. Appl. Phys. Lett., 2020, 116: 081101.

[45] [45] Watschke L, Passow T, Fuchs F, et al. AlGaN avalanche Schottky diodes with high Alcontent[J]. Jap. J. of Appl. Phys., 2019, 58: SCCC11.