Preparation and research progress of GaN-based avalanche photodetectors

Abstract

The demand for single-photon high-sensitivity ultraviolet (UV) detection is continuously increasing in cutting-edge fields such as UV astronomy, environmental monitoring, and space communications. In particular, gallium nitride (GaN) is an ideal material for UV detection due to its wide bandgap (3.4 eV), strong radiation immunity, and visible/solar-blind properties. In this respect, avalanche photodetectors (APDs) are very promising candidates for single-photon UV detection due to their high sensitivity, large gain, high detection efficiency, and room temperature operation. This review summarizes the GaN avalanche breakdown characteristics, including current surge, positive temperature coefficient of V_br, and non-linear characterization. In addition, recent advances in various structural types of GaN APDs, such as p-i-n, separated absorption multiplication, optimized edge termination, and polarization-enhanced structures, are presented. In addition, the directions and challenges for the future development of GaN APDs are discussed. Although GaN-based APDs have significantly improved their UV single-photon detection performance through structural innovations, noise control, linearity optimization, and process simplification remain the core challenges. In the future, the integration with two-dimensional material heterojunction and new light trapping structure is expected to break through the existing bottleneck and promote its application in frontier fields such as deep space exploration and quantum communication.

Keywords

GaN / avalanche photodetector / SAM / p-i-n photodiode

References

[1] Razeghi M.Semiconductor ultraviolet detectors.J Appl Phys1996;79:7433-73

[2] Tang X,Yu D,Zhang S.Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin.Environ Int2024;185:108535

[3] Caldwell M,Bornman J.Effects of increased solar ultraviolet radiation on terrestrial ecosystems.J Photoch Photobio B1998;46:40-52

[4] Maccarone MC,Catalano O.UVscope and its application aboard the ASTRI-Horn telescope.Exp Astron2021;51:529-50

[5] Su L,Lu H,Zheng Y.Recent progress of SiC UV single photon counting avalanche photodiodes.J Semicond2019;40:121802

[6] Smith JP,Cuda A,Mazin BA.MKIDGen3: Energy-resolving, single-photon-counting microwave kinetic inductance detector readout on a radio frequency system-on-chip.Rev Sci Instrum2024;95:114705

[7] Boukhicha M,Giacomini G,Cultrera L.UV hybrid photon detector based on GaN photocathodes and Si low gain avalanche diode.J Inst2024;19:P07020

[8] Adams JH,Alldredge P.The EUSO-SPB2 fluorescence telescope for the detection of ultra-high energy cosmic rays.Astropart Phys2025;165:103046

[9] Zheng W,Huang F.Vacuum-ultraviolet photon detections.iScience2020;23:101145 PMCID:PMC7243193

[10] Su L,Xie J.An all-inorganic CsPbBr₃/GaN hetero-structure for a near UV to green band photodetector.J Mater Chem C2022;10:1349-56

[11] Liu J,Kumar S.Time-controlled SPAD receivers in optical wireless communication system.IEEE Photonics J2023;15:1-13

[12] Ribisch C,Kohneh Poushi SS.Multi-channel gating chip in 0.18 µm high-voltage CMOS for quantum applications.Sensors (Basel)2023;23:9644 PMCID:PMC10747136

[13] Chen H,Lu J.Toward long-distance underwater wireless optical communication based on a high-sensitivity single photon avalanche diode.IEEE Photonics J2020;12:1-10

[14] Hippke M.Interstellar communication: short pulse duration limits of optical SETI.J Astrophys Astron2018;39:9565

[15] Hippke M.Searching for interstellar quantum communications.AJ2021;162:1

[16] Antolovic IM,Bruschini C,Charbon E.Nonuniformity analysis of a 65-kpixel CMOS SPAD imager.IEEE Trans Electron Devices2016;63:57-64

[17] Zhang Y,Tong X,Cao R.Quantum imaging of biological organisms through spatial and polarization entanglement.Sci Adv2024;10:eadk1495 PMCID:PMC10923495

[18] Van den Dries T,Janssen S.64 × 64 pixel current-assisted photonic sampler image sensor and camera system for real-time fluorescence lifetime imaging.IEEE Sensors J2024;24:23729-37

[19] Liu Q,Jin Y.Ultraviolet response in coplanar silicon avalanche photodiodes with CMOS compatibility.Sensors (Basel)2022;22:3873 PMCID:PMC9146899

[20] Alirezaei IS,Flandre D.Enhanced ultraviolet avalanche photodiode with 640-nm-thin silicon body based on SOI technology.IEEE Trans Electron Devices2020;67:4641-4

[21] Guo G,Zheng K.Research on the structure design of silicon avalanche photodiode with near-ultraviolet high responsivity.Photonics2024;11:1

[22] Jimenéz-Vivanco MR,Carrillo J.Porous Si-SiO₂ UV microcavities to modulate the responsivity of a broadband photodetector.Nanomaterials (Basel)2020;10:222 PMCID:PMC7075018

[23] Li G,Guo Z.Recent advances in III-V nitrides: properties, applications and perspectives.J Mater Chem C2024;12:12150-78

[24] Chen K,Zou C.Two-in-one: end-emitting blue LED and self-powered UV photodetector based on single trapezoidal PIN GaN microwire for ambient light UV monitoring and feedback.Small Methods2023;7:e2300138

[25] Morkoç H,Gao GB,Sverdlov B.Large-band-gap SiC, III-V nitride, and II-VI ZnSe-based semiconductor device technologies.J Appl Phys1994;76:1363-98

[26] Östling M.High power devices in wide bandgap semiconductors.Sci China Inf Sci2011;54:1087-93

[27] Chen X,Jian J,Zhang Z.Effect of strain on space charge layer in GaN nanowires investigated by in-situ off-axis electron holography.Prog Nat Sci: Mater Int2017;27:186-91

[28] Hassan A,Sawan M.GaN Integration technology, an ideal candidate for high-temperature applications: a review.IEEE Access2018;6:78790-802

[29] Kozodoy P,Denbaars S.MOVPE growth and characterization of Mg-doped GaN.J Cryst Growth1998;195:265-9

[30] Cai Q,Yuan R.Back-illuminated AlGaN heterostructure solar-blind avalanche photodiodes with one-dimensional photonic crystal filter.Opt Express2020;28:6027-35

[31] Sun Z,Zhao D.Investigation of the leakage mechanism in solar-blind AlGaN p-i-n photodetector at high reverse bias.J Appl Phys2024;136:175701

[32] Wang H,Pan D.Polarization enhanced GaN avalanche photodiodes with p-type In_0.05Ga_0.95N layer.IEEE Photonics J2020;12:1-6

[33] Kizilyalli IC,Nie H,Bour D.High voltage vertical GaN p-n diodes with avalanche capability.IEEE Trans Electron Devices2013;60:3067-70

[34] Liu J,Zhang R.1.2-kV vertical GaN fin-JFETs: high-temperature characteristics and avalanche capability.IEEE Trans Electron Devices2021;68:2025-32

[35] Dyakonova N,Shur MS,Yang JW.Temperature dependence of impact ionization in AlGaN-GaN heterostructure field effect transistors.Appl Phys Lett1998;72:2562-4

[36] Tut T,Butun B,Ulker E.Experimental evaluation of impact ionization coefficients in Al_xGa_1-xN based avalanche photodiodes.Appl Phys Lett2006;89:183524

[37] Sun L,Li J.AlGaN solar-blind avalanche photodiodes with high multiplication gain.Appl Phys Lett2010;97:191103

[38] Huang Y,Lu H.Back-illuminated separate absorption and multiplication AlGaN solar-blind avalanche photodiodes.Appl Phys Lett2012;101:253516

[39] Massey D,Rees G.Temperature dependence of impact ionization in submicrometer silicon devices.IEEE Trans Electron Devices2006;53:2328-34

[40] Jeong H,Xu Z.Ion-implanted Al_0.6Ga_0.4N deep-ultraviolet avalanche photodiodes.Appl Phys Lett2023;123:121107

[41] Gan H,Wang X.Enhancing linearity of light response in avalanche photodiodes by suppressing electrode size effect.Sensors (Basel)2024;24:3366 PMCID:PMC11174770

[42] Osinsky A,Gaska R.Avalanche breakdown and breakdown luminescence in p-π-n GaN diodes.Electron Lett1998;34:691-2

[43] Carrano JC,Eiting CJ.GaN avalanche photodiodes.Appl Phys Lett2000;76:924-6

[44] Butun B,Ulker E,Ozbay E.High-performance visible-blind GaN-based p-i-n photodetectors.Appl Phys Lett2008;92:033507

[45] Gautam L,Richards M.Solar-blind deep UV avalanche photodetectors using reduced area epitaxy.IEEE J Quantum Electron2023;59:1-4

[46] Limb JB,Ryou JH.GaN ultraviolet avalanche photodiodes with optical gain greater than 1000 grown on GaN substrates by metal-organic chemical vapor deposition.Appl Phys Lett2006;89:011112

[47] Shyh-chiang Shen,Dongwon Yoo.Performance of deep ultraviolet GaN avalanche photodiodes grown by MOCVD.IEEE Photon Technol Lett2007;19:1744-6

[48] Yoo D,Ryou J.Al_xGa_1-xN ultraviolet avalanche photodiodes grown on GaN substrates.IEEE Photon Technol Lett2007;19:1313-5

[49] Zhang Y,Kim HJ.Low-noise GaN ultraviolet p-i-n photodiodes on GaN substrates.Appl Phys Lett2009;94:221109

[50] Kim J,Detchprohm T.Comparison of AlGaN p-i-n ultraviolet avalanche photodiodes grown on free-standing GaN and sapphire substrates.Appl Phys Express2015;8:122202

[51] Li J,Yan X.GaN p-i-n ultraviolet photodetectors grown on homogenous GaN bulk substrates.Solid-State Electronics2022;197:108419

[52] Fukushima H,Ogura M.Deeply and vertically etched butte structure of vertical GaN p-n diode with avalanche capability.Jpn J Appl Phys2019;58:SCCD25

[53] Vashaei Z,Bayram C,Razeghi M.GaN avalanche photodiodes grown on m-plane freestanding GaN substrate.Appl Phys Lett2010;96:201908

[54] Gautam L,Brown G.Low dark current deep UV AlGaN photodetectors on AlN substrate.IEEE J Quantum Electron2022;58:1-5

[55] Cicek E,Mcclintock R,Razeghi M.Geiger-mode operation of ultraviolet avalanche photodiodes grown on sapphire and free-standing GaN substrates.Appl Phys Lett2010;96:261107

[56] Wei Y,Qu H.GaN-based low-energy X-ray single photon detector with photon energy resolution and fast response.IEEE Photon Technol Lett2024;36:123-6

[57] Chen Y,Jiang H,Miao G.The optimized growth of AlN templates for back-illuminated AlGaN-based solar-blind ultraviolet photodetectors by MOCVD.J Mater Chem C2018;6:4936-42

[58] Kim J,Detchprohm T.Al_xGa_1-xN Ultraviolet avalanche photodiodes with avalanche gain greater than 10⁵.IEEE Photon Technol Lett2015;27:642-5

[59] Mcclintock R,Minder K,Kung P.Hole-initiated multiplication in back-illuminated GaN avalanche photodiodes.Appl Phys Lett2007;90:141112

[60] Maeda T,Yamada S.Impact ionization coefficients and critical electric field in GaN.J Appl Phys2021;129:185702

[61] Cao L,Harden G.Experimental characterization of impact ionization coefficients for electrons and holes in GaN grown on bulk GaN substrates.Appl Phys Lett2018;112:262103

[62] Ji D,Chowdhury S.Experimental determination of impact ionization coefficients of electrons and holes in gallium nitride using homojunction structures.Appl Phys Lett2019;115:073503

[63] Jeong H,Xu Z.Breakdown characteristics of deep-ultraviolet Al_0.6Ga_0.4N p-i-n avalanche photodiodes.J Appl Phys2022;131:103102

[64] Shao ZG,You HF.Ionization-enhanced AlGaN heterostructure avalanche photodiodes.IEEE Electron Device Lett2017;38:485-8

[65] Bayram C,Mcclintock R,Ulmer MP.High quantum efficiency back-illuminated GaN avalanche photodiodes.Appl Phys Lett2008;93:211107

[66] Minder K,Mcclintock R.Scaling in back-illuminated GaN avalanche photodiodes.Appl Phys Lett2007;91:073513

[67] Ji D,Benson G,Chowdhury S.60 A/W high voltage GaN avalanche photodiode demonstrating robust avalanche and high gain up to 525 K.Appl Phys Lett2020;116:211102

[68] Campbell J,Holden W.High-performance avalanche photodiode with separate absorption ‘grading’ and multiplication regions.Electron Lett (UK)1983;19:818-20

[69] Mcintyre R.Multiplication noise in uniform avalanche diodes.IEEE Trans Electron Devices1966;ED-13:164-8

[70] Zhang Z,Chen M,Li B.Separate absorption and multiplication AlGaN solar-blind avalanche photodiodes with high-low-doped and heterostructured charge layer.J Elec Materi2020;49:2343-8

[71] Ji M,Detchprohm T,Shen S.p-i-p-i-n separate absorption and multiplication ultraviolet avalanche photodiodes.IEEE Photon Technol Lett2018;30:181-4

[72] Cao J,You H.Observation of photoelectric-induced microplasma avalanche breakdown in AlGaN ultraviolet photodiode with separate absorption and multiplication structure.Appl Phys Lett2023;123:121109

[73] Ohta H,Horikiri F,Yoshida T.4.9 kV breakdown voltage vertical GaN p-n junction diodes with high avalanche capability.Jpn J Appl Phys2019;58:SCCD03

[74] Nomoto K,Song B.GaN-on-GaN p-n power diodes with 3.48 kV and 0.95 mΩ-cm²: a record high figure-of-merit of 12.8 GW/cm². In 2015 IEEE international electron devices meeting, Proceedings of the 2015 IEEE international electron devices meeting (IEDM), Washington, DC, USA, December 7-9, 2015; IEEE Publisher: Piscataway, New Jersey, USA, 2015; pp 9.7.1-9.7.4.

[75] Liu J,Zhang R.Trap-mediated avalanche in large-area 1.2 kV vertical GaN p-n diodes.IEEE Electron Device Lett2020;41:1328-31

[76] Matys M,Nam KP.Design and demonstration of nearly-ideal edge termination for GaN p-n junction using Mg-implanted field limiting rings.Appl Phys Express2021;14:074002

[77] Matys M,Nam KP.Mg-implanted bevel edge termination structure for GaN power device applications.Appl Phys Lett2021;118:093502

[78] Duan Y,Fay P.1.7-kV vertical GaN p-n diodes with step-graded ion-implanted edge termination. In 2023 Device Research Conference (DRC), Proceedings of the 2023 Device Research Conference (DRC), Santa Barbara, CA, USA, June 25-28, 2023; IEEE Publisher: Piscataway, New Jersey, USA, 2023; pp 1-2.

[79] You H,Luo W.High-performance Al_0.1Ga_0.9N p-i-n ultraviolet avalanche photodiodes with ultra-shallow bevel edge terminations.IEEE Electron Device Lett2024;45:869-72

[80] Xu Z,Shen S,Dupuis RD.Low leakage and high gain GaN p-i-n avalanche photodiode with shallow bevel mesa edge termination and recessed window.IEEE Trans Electron Devices2024;71:3761-8

[81] Shoji T,Nagasato Y.Analysis of intrinsic reverse leakage current resulting from band-to-band tunneling in dislocation-free GaN p-n junctions.Appl Phys Express2021;14:114001

[82] Maeda T,Yamada S.Impact ionization coefficients in GaN measured by above-and sub-E_g illuminations for p^-/n⁺ junction. In 2019 IEEE international electron devices meeting, Proceedings of the 2019 IEEE international electron devices meeting (IEDM), San Francisco, CA, USA, December 7-11, 2019; IEEE Publisher: Piscataway, New Jersey, USA, 2019; pp 4.2.1-4.2.4.

[83] You H,Luo W.Al_0.1Ga_0.9N p-i-n ultraviolet avalanche photodiodes with avalanche gain over 10⁶.IEEE Electron Device Lett2022;43:1479-82

[84] You H,Luo W.Al_0.1Ga_0.9N p-i-n ultraviolet avalanche photodiodes with suppressed surface leakage current and uniform avalanche breakdown.Opt Express2023;31:37516-22

[85] Wang W.Uniform and high gain GaN p-i-n ultraviolet APDs enabled by beveled-mesa edge termination.IEEE Photon Technol Lett2020;32:1357-60

[86] Yuhao Zhang,Hiu-yung Wong.Origin and control of OFF-state leakage current in GaN-on-Si vertical diodes.IEEE Trans Electron Devices2015;62:2155-61

[87] Fu H,Huang X.High performance vertical GaN-on-GaN p-n power diodes with hydrogen-plasma-based edge termination.IEEE Electron Device Lett2018;39:1018-21

[88] Fu H,Liu H.Implantation-and etching-free high voltage vertical GaN p-n diodes terminated by plasma-hydrogenated p-GaN: revealing the role of thermal annealing.Appl Phys Express2019;12:051015

[89] Fu H,Alugubelli SR.High voltage vertical GaN p-n diodes with hydrogen-plasma based guard rings.IEEE Electron Device Lett2020;41:127-30

[90] Fu K,Yang C,Fu H.GaN-on-GaN p-i-n diodes with avalanche capability enabled by eliminating surface leakage with hydrogen plasma treatment.Appl Phys Lett2022;121:092103

[91] Zheng B,Yu C.Suppression of current leakage along mesa surfaces in GaN-based p-i-n diodes.IEEE Electron Device Lett2015;36:932-4

[92] Cho M,Bakhtiary-noodeh M.1.2-kV vertical GaN PIN rectifier with Ion-implanted floating guard rings.IEEE Trans Electron Devices2023;70:4578-83

[93] Wang W,Li Q.Surface smoothing with BCl₃ plasma post-treatment to improve the performance of GaN avalanche photodiodes.Jpn J Appl Phys2019;58:106505

[94] Sheen M,Kim DU.Highly efficient blue InGaN nanoscale light-emitting diodes.Nature2022;608:56-61

[95] Han S,Sheng K.High-voltage and High-I_ON/I_OFF vertical GaN-on-GaN schottky barrier diode with nitridation-based termination.IEEE Electron Device Lett2018;39:572-5

[96] Cao J,You H.Temperature dependent low-frequency noise characteristics of AlGaN avalanche photodiodes with ultra-shallow bevel edge termination.J Alloys Compd2025;1010:177934

[97] Bulmer J,Leathersich J.Visible-blind APD heterostructure design with superior field confinement and low operating voltage.IEEE Photon Technol Lett2016;28:39-42

[98] Wang J,Hou Q.Polarization enhanced GaN separate absorption and multiplication ultraviolet avalanche photodiodeswith an ScGaN interlayer.Opt Lett2024;49:6713-6

[99] Guo J,Gu Y.Improved performance of AlGaN solar-blind avalanche photodiodes with dual multiplication layers.Opt Quant Electron2023;55:4400

[100] Sun Z,Zhao D.The effect of nanopipes and an inserted n-AlGaN interlayer on GaN avalanche photodiodes performance.Physica Status Solidi (a)2024;221:2300490

[101] Yu C,Tsai JY,Wang SC.Electrical and optical properties of beryllium-implanted Mg-doped GaN.J Appl Phys2002;92:1881-7

[102] Wang D,He M.Fully epitaxial, monolithic ScAlN/AlGaN/GaN ferroelectric HEMT.Appl Phys Lett2023;122:090601

[103] Moram MA.ScGaN and ScAlN: emerging nitride materials.J Mater Chem A2014;2:6042-50

[104] Hirata K,Uehara M,Anggraini SA.Effect of phase transition on the piezoelectric properties of scandium-alloyed gallium nitride.J Appl Phys2024;135:164101

[105] Bellotti E.A numerical study of carrier impact ionization in Al_xGa_1-xN.J Appl Phys2012;111:103711

[106] Cai Z,Zhou P.The development of transfer technologies for advanced 2D circuits integration.Inf Funct Mater2024;1:304-22

[107] Yang X,Cheng S,Zang JH.An ultraviolet-visible distinguishable broadband photodetector based on the positive and negative photoconductance effects of a graphene/ZnO quantum dot heterostructure.Microstructures2022;3:6

[108] Zhang C,Zhang D,Sun W.Two-dimensional germanium for photocatalysis.Inf Funct Mater2024;1:108-23

[109] Cai Q,Li Q.AlGaN ultraviolet Avalanche photodiodes based on a triple-mesa structure.Appl Phys Lett2018;113:123503

[110] Gautam L,Lee J,Razeghi M.Geiger-mode operation of AlGaN avalanche photodiodes at 255 nm.IEEE J Quantum Electron2021;57:1-6

[111] Verghese S,Molnar R.GaN avalanche photodiodes operating in linear-gain mode and Geiger mode.IEEE Trans Electron Devices48:502-11

[112] Zhou Q,Lu Z.GaN/SiC avalanche photodiodes.Appl Phys Lett2011;99:131110

[113] Gao L,You J.Broadband and ultra-high-sensitivity separate absorption-multiplication avalanche phototransistor based on a Au-WSe₂-Ge heterostructure.ACS Photonics2023;10:4349-56

[114] Chen K,Liu Q.Graphene/GaN ultraviolet photodetector performance regulated by a HfO₂ insulating layer.Appl Phys Lett2024;124:052103

[115] Liu Q,Wang X.Fowler-Nordheim tunneling mechanism for performance improvement in graphene 2D/GaN 3D heterojunction ultraviolet photodetector.Carbon2023;201:1061-7

[116] Zhao Z,Zhou E.Interface engineering by inserting Al₂O₃ tunneling layer to enhance the performance of graphene/GaAs heterojunction photodetector.Surf Interfaces2023;39:102909

[117] Gao A,Wang Y.Observation of ballistic avalanche phenomena in nanoscale vertical InSe/BP heterostructures.Nat Nanotechnol2019;14:217-22

[118] Son B,Luo M.Efficient avalanche photodiodes with a WSe₂/MoS₂ heterostructure via two-photon absorption.Nano Lett2022;22:9516-22

[119] Xia H,Wang W.Pristine PN junction toward atomic layer devices.Light Sci Appl2022;11:170 PMCID:PMC9167816

[120] Meng L,Yang M.Low-voltage and high-gain WSe₂ avalanche phototransistor with an out-of-plane WSe₂/WS₂ heterojunction.Nano Res2023;16:3422-8

[121] Wang H,Liu Y.Room-temperature low-threshold avalanche effect in stepwise van-der-Waals homojunction photodiodes.Nat Commun2024;15:3639 PMCID:PMC11059283

[122] Chen D,Jones AH.Photon-trapping-enhanced avalanche photodiodes for mid-infrared applications.Nat Photon2023;17:594-600

[123] Butun S,Ozbay E.Nanoantenna coupled UV subwavelength photodetectors based on GaN.Opt Express2012;20:2649-56

[124] Ahmadivand A,Vabbina PK,Kaya S.Hot electron generation by aluminum oligomers in plasmonic ultraviolet photodetectors.Opt Express2016;24:13665-78

[125] Dubey A,Hsieh YH.Aluminum plasmonics enriched ultraviolet GaN photodetector with ultrahigh responsivity, detectivity, and broad bandwidth.Adv Sci (Weinh)2020;7:2002274 PMCID:PMC7740085

[126] Xu T,Tang K.On-chip integrated plasmon-induced high-performance self-powered Pt/GaN ultraviolet photodetector.Chip2025;4:100118

[127] An Y,Huang Y.Au plasmon enhanced high performance β-Ga₂O₃ solar-blind photo-detector.Prog Nat Sci: Mater Int2016;26:65-8

[128] Ling Y,Yang Y.Polarity modulation of hot electron transfer in plasmonic Au nanoparticle/GaN heterojunctions: implications for quantum efficient plasmon-driven devices.ACS Appl Nano Mater2024;7:16352-9