Fig. 1.
(Color online) Graphical abstract reflecting areas explored in this review article.
DownLoad:
| Citation: |
Nasir Alfaraj, Jung-Wook Min, Chun Hong Kang, Abdullah A. Alatawi, Davide Priante, Ram Chandra Subedi, Malleswararao Tangi, Tien Khee Ng, Boon S. Ooi. Deep-ultraviolet integrated photonic and optoelectronic devices: A prospect of the hybridization of group III–nitrides, III–oxides, and two-dimensional materials[J]. Journal of Semiconductors, 2019, 40(12): 121801. doi: 10.1088/1674-4926/40/12/121801
N Alfaraj, J W Min, C H Kang, A A Alatawi, D Priante, R C Subedi, M Tangi, T K Ng, B S Ooi, Deep-ultraviolet integrated photonic and optoelectronic devices: A prospect of the hybridization of group III–nitrides, III–oxides, and two-dimensional materials[J]. J. Semicond., 2019, 40(12): 121801. doi: 10.1088/1674-4926/40/12/121801.
Export: BibTex EndNote
|
Deep-ultraviolet integrated photonic and optoelectronic devices: A prospect of the hybridization of group III–nitrides, III–oxides, and two-dimensional materials
doi: 10.1088/1674-4926/40/12/121801
More Information-
Abstract
Progress in the design and fabrication of ultraviolet and deep-ultraviolet group III–nitride optoelectronic devices, based on aluminum gallium nitride and boron nitride and their alloys, and the heterogeneous integration with two-dimensional and oxide-based materials is reviewed. We emphasize wide-bandgap nitride compound semiconductors (i.e., (B, Al, Ga)N) as the deep-ultraviolet materials of interest, and two-dimensional materials, namely graphene, two-dimensional boron nitride, and two-dimensional transition metal dichalcogenides, along with gallium oxide, as the hybrid integrated materials. We examine their crystallographic properties and elaborate on the challenges that hinder the realization of efficient and reliable ultraviolet and deep-ultraviolet devices. In this article we provide an overview of aluminum nitride, sapphire, and gallium oxide as platforms for deep-ultraviolet optoelectronic devices, in which we criticize the status of sapphire as a platform for efficient deep-ultraviolet devices and detail advancements in device growth and fabrication on aluminum nitride and gallium oxide substrates. A critical review of the current status of deep-ultraviolet light emission and detection materials and devices is provided.-
Keywords:
- deep-ultraviolet,
- ultraviolet,
- photonics,
- optoelectronics,
- hybrid
-
References
[1] Wang L, Xie R J, Suehiro T, et al. Down-conversion nitride materials for solid state lighting: Recent advances and perspectives. Chem Rev, 2018, 118, 1951 doi: 10.1021/acs.chemrev.7b00284[2] Alhassan A I, Young N G, Farrell R M, et al. Development of high performance green c-plane III-nitride light-emitting diodes. Opt Express, 2018, 26, 5591 doi: 10.1364/OE.26.005591[3] Pimputkar S, Speck J S, DenBaars S P, et al. Prospects for LED lighting. Nat Photonics, 2009, 3, 180 doi: 10.1038/nphoton.2009.32[4] Kim J S, Jeon P E, Park Y H, et al. White-light generation through ultraviolet-emitting diode and white-emitting phosphor. Appl Phys Lett, 2004, 85, 3696 doi: 10.1063/1.1808501[5] Matafonova G, Batoev V. Recent advances in application of UV light-emitting diodes for degrading organic pollutants in water through advanced oxidation processes: A review. Water Res, 2018, 132, 177 doi: 10.1016/j.watres.2017.12.079[6] Chen J, Loeb S, Kim J H. LED revolution: fundamentals and prospects for UV disinfection applications. Environ Sci: Water Res Technol, 2017, 3, 188 doi: 10.1039/C6EW00241B[7] Chen Q, Zhang H, Dai J. Enhanced the optical power of AlGaN-based deep ultraviolet light-emitting diode by optimizing mesa sidewall angle. IEEE Photonics J, 2018, 10, 6100807 doi: 10.1109/JPHOT.2018.2850038[8] Hirayama H, Fujikawa S, Kamata N. Recent progress in AlGaN-based deep-UV LEDs. Electron Commun Jpn, 2015, 98, 1 doi: 10.1002/ecj.11667[9] Aoyagi Y, Takeuchi M, Yoshida K, et al. High-sensitivity ozone sensing using 280 nm deep ultraviolet light-emitting diode for detection of natural hazard ozone. J Environ Prot, 2012, 3, 695 doi: 10.4236/jep.2012.38082[10] Würtele M, Kolbe T, Lipsz M, et al. Application of GaN-based ultraviolet-C light emitting diodes-UV LEDs-for water disinfection. Water Res, 2011, 45, 1481 doi: 10.1016/j.watres.2010.11.015[11] Alhamoud A A, Alfaraj N, Priante D, et al. Functional integrity and stable high-temperature operation of planarized ultraviolet-A AlxGa1−xN/AlyGa1−yN multiple-quantum-disk nanowire LEDs with charge-trapping inhibition interlayer. Gallium Nitride Materials and Devices XIV. Vol. 10918, 2019, 109181X[12] Jasuja K, Ayinde K, Wilson C L, et al. Introduction of protonated sites on exfoliated, large-area sheets of hexagonal boron nitride. ACS Nano, 2018, 12, 9931 doi: 10.1021/acsnano.8b03651[13] Pacilé D, Meyer J C, Girit Ç Ö, et al. The two-dimensional phase of boron nitride: Few-atomic-layer sheets and suspended membranes. Appl Phys Lett, 2008, 92, 133107 doi: 10.1063/1.2903702[14] Srinivasan S, Stevens M, Ponce F A, et al. Carrier dynamics and electrostatic potential variation in InGaN quantum wells grown on\scriptsize$ \left\{ {11\bar 22} \right\}$ GaN pyramidal planes. Appl Phys Lett, 2006, 89, 231908 doi: 10.1063/1.2397566[15] ElAfandy R T, Majid M A, Ng T K, et al. Exfoliation of threading dislocation-free, singlecrystalline, ultrathin gallium nitride nanomembranes. Adv Funct Mater, 2014, 24, 2305 doi: 10.1002/adfm.v24.16[16] Hirayama H. Ultraviolet LEDs. In: Nitride Semiconductor Light-Emitting Diodes (LEDs). Elsevier, 2014, 497[17] Orji N G, Badaroglu M, Barnes B M, et al. Metrology for the next generation of semiconductor devices. Nat Electron, 2018, 1, 532 doi: 10.1038/s41928-018-0150-9[18] Ayari T, Sundaram S, Li X, et al. Heterogeneous integration of thin-film InGaN-based solar cells on foreign substrates with enhanced performance. ACS Photonics, 2018, 5, 3003 doi: 10.1021/acsphotonics.8b00663[19] Liu S, Sheng B, Wang X, et al. Molecular beam epitaxy of single-crystalline aluminum film for low threshold ultraviolet plasmonic nanolasers. Appl Phys Lett, 2018, 112, 231904 doi: 10.1063/1.5033941[20] Yuan C, Pomeroy J W, Kuball M. Above bandgap thermoreflectance for non-invasive thermal characterization of GaN-based wafers. Appl Phys Lett, 2018, 113, 102101 doi: 10.1063/1.5040100[21] Jiang J, Guo W, Xu H, et al. Performance enhancement of ultraviolet light emitting diode incorporating Al nanohole arrays. Nanotechnology, 2018, 29, 45LT01 doi: 10.1088/1361-6528/aaddc8[22] Ishibe T, Kurokawa T, Naruse N, et al. Resistive switching at the high quality metal/insulator interface in Fe3O4/SiO2/α-FeSi2/Si stacking structure. Appl Phys Lett, 2018, 113, 141601 doi: 10.1063/1.5048827[23] Priante D, Janjua B, Prabaswara A, et al. Highly uniform ultraviolet-A quantum-confined AlGaN nanowire LEDs on metal/silicon with a TaN interlayer. Opt Mater Express, 2017, 7, 4214 doi: 10.1364/OME.7.004214[24] Sumikura H, Kuramochi E, Notomi M. Nonlinear optical absorption of beryllium isoelectronic centers doped in silicon waveguides. Appl Phys Lett, 2018, 113, 141101 doi: 10.1063/1.5046336[25] Priante D, Janjua B, Prabaswara A, et al Ti/TaN bilayer for efficient injection and reliable AlGaN nanowires LEDs. Conference on Lasers and ElectroOptics, 2018, JTu2A.91[26] Zhang R, Zhao B, Huang K, et al. Silicon-on-insulator with hybrid orientations for heterogeneous integration of GaN on Si (100) substrate. AIP Adv, 2018, 8, 055323 doi: 10.1063/1.5030776[27] Patil S S, Johar M A, Hassan M A, et al. Anchoring MWCNTs to 3D honeycomb ZnO/GaN heterostructures to enhancing photoelectrochemical water oxidation. Appl Catal B, 2018, 237, 791 doi: 10.1016/j.apcatb.2018.06.047[28] Ajima Y, Nakamura Y, Murakami K, et al. Room-temperature bonding of GaAs//Si and GaN//GaAs wafers with low electrical resistance. Appl Phys Express, 2018, 11, 106501 doi: 10.7567%2Fapex.11.106501[29] Liu X, Sun C, Xiong B, et al. Generation of multiple near-visible comb lines in an AlN microring via χ(2) and χ(3) optical nonlinearities. Appl Phys Lett, 2018, 113, 171106 doi: 10.1063/1.5046324[30] Zhao C, Alfaraj N, Subedi R C, et al. III-nitride nanowires on unconventional substrates: From materials to optoelectronic device applications. Prog Quantum Electron, 2018, 61, 1 doi: 10.1016/j.pquantelec.2018.07.001[31] Houlton J P, Brubaker M D, Martin D O, et al. An optical Bragg scattering readout for nano-mechanical resonances of GaN nanowire arrays. Appl Phys Lett, 2018, 113, 123102 doi: 10.1063/1.5043211[32] Maity A, Grenadier S J, Li J, et al. Hexagonal boron nitride neutron detectors with high detection efficiencies. J Appl Phys, 2018, 123, 044501 doi: 10.1063/1.5017979[33] Maity A, Grenadier S J, Li J, et al. Toward achieving flexible and high sensitivity hexagonal boron nitride neutron detectors. Appl Phys Lett, 2017, 111, 033507 doi: 10.1063/1.4995399[34] Ahmed K, Dahal R, Weltz A, et al. Solid-state neutron detectors based on thickness scalable hexagonal boron nitride. Appl Phys Lett, 2017, 110, 023503 doi: 10.1063/1.4973927[35] Alden D, Troha T, Kirste R, et al. Quasi-phase-matched second harmonic generation of UV light using AlN waveguides. Appl Phys Lett, 2019, 114, 103504 doi: 10.1063/1.5087058[36] Bruch A W, Liu X, Guo X, et al. 17000%/W second-harmonic conversion efficiency in single-crystalline aluminum nitride microresonators. Appl Phys Lett, 2018, 113, 131102 doi: 10.1063/1.5042506[37] Du C, Hu W, Wang Z L. Recent progress on piezotronic and piezo-phototronic effects in III-group nitride devices and applications. Adv Eng Mater, 2018, 20, 1700760 doi: 10.1002/adem.v20.5[38] Kim H J, Jung S I, Segovia-Fernandez J, et al. The impact of electrode materials on 1/f noise in piezoelectric AlN contour mode resonators. AIP Adv, 2018, 8, 055009 doi: 10.1063/1.5024961[39] Cassella C, Chen G, Qian Z, et al. RF passive components based on aluminum nitride crosssectional lamé-mode MEMS resonators. IEEE Trans Electron Devices, 2017, 64, 237 doi: 10.1109/TED.2016.2621660[40] Wang X, Song J, Zhang F, et al. Electricity generation based on one-dimensional group-III nitride nanomaterials. Adv Mater, 2010, 22, 2155 doi: 10.1002/adma.v22:19[41] Yu R, Wu W, Ding Y, et al. GaN nanobelt-based strain-gated piezotronic logic devices and computation. ACS Nano, 2013, 7, 6403 doi: 10.1021/nn4026788[42] Zhang H, Zhang Q, Lin M, et al. A GaN/InGaN/AlGaN MQW RTD for versatile MVL applications with improved logic stability. J Semicond, 2018, 39, 074004 doi: 10.1088/1674-4926/39/7/074004[43] Springbett H, Gao K, Jarman J, et al. Improvement of single photon emission from InGaN QDs embedded in porous micropillars. Appl Phys Lett, 2018, 113, 101107 doi: 10.1063/1.5045843[44] Bourrellier R, Meuret S, Tararan A, et al. Bright UV single photon emission at point defects in h-BN. Nano Lett, 2016, 16, 4317 doi: 10.1021/acs.nanolett.6b01368[45] Vuong T, Cassabois G, Valvin P, et al. Phonon-photon mapping in a color center in hexagonal boron nitride. Phys Rev Lett, 2016, 117, 097402 doi: 10.1103/PhysRevLett.117.097402[46] Elafandy R T, Ebaid M, Min J W, et al. Flexible InGaN nanowire membranes for enhanced solar water splitting. Opt Express, 2018, 26, A640 doi: 10.1364/OE.26.00A640[47] Zhang H, Ebaid M, Min J W, et al. Enhanced photoelectrochemical performance of InGaN-based nanowire photoanodes by optimizing the ionized dopant concentration. J Appl Phys, 2018, 124, 083105 doi: 10.1063/1.5031067[48] Kim Y J, Lee G J, Kim S, et al. Efficient light absorption by GaN truncated nanocones for high performance water splitting applications. ACS Appl Mater Interfaces, 2018, 10, 28672 doi: 10.1021/acsami.8b09084[49] Ebaid M, Min J W, Zhao C, et al. Water splitting to hydrogen over epitaxially grown InGaN nanowires on a metallic titanium/silicon template: reduced interfacial transfer resistance and improved stability to hydrogen. J Mater Chem A, 2018, 6, 6922 doi: 10.1039/C7TA11338B[50] Ebaid M, Priante D, Liu G, et al. Unbiased photocatalytic hydrogen generation from pure water on stable Ir-treated In0.33Ga0.67N nanorods. Nano Energy, 2017, 37, 158 doi: 10.1016/j.nanoen.2017.05.013[51] Sekimoto T, Hashiba H, Shinagawa S, et al. Wireless InGaN-Si/Pt device for photo-electrochemical water splitting. Jpn J Appl Phys, 2016, 55, 088004 doi: 10.7567/JJAP.55.088004[52] Lin C H, Fu H C, Cheng B, et al. A flexible solar-blind 2D boron nitride nanopaper-based photodetector with high thermal resistance. NPJ 2D Mater Appl, 2018, 2, 23 doi: 10.1038/s41699-018-0070-6[53] Tan X, Lv Y J, Zhou X Y, et al. AlGaN/GaN pressure sensor with a Wheatstone bridge structure. AIP Adv, 2018, 8, 085202 doi: 10.1063/1.4996257[54] Mehnke F, Guttmann M, Enslin J, et al. Gas sensing of nitrogen oxide utilizing spectrally pure deep UV LEDs. IEEE J Sel Top Quantum Electron, 2017, 23, 29 doi: 10.1109/JSTQE.2016.2597541[55] Pyo J Y, Jeon J H, Koh Y, et al. AlGaN/GaN high-electronmobility transistor pH sensor with extended gate platform. AIP Adv, 2018, 8, 085106 doi: 10.1063/1.5041847[56] Cao H, Ma Z, Sun B, et al. Composite degradation model and corresponding failure mechanism for mid-power GaN-based white LEDs. AIP Adv, 2018, 8, 065108 doi: 10.1063/1.5027783[57] Janjua B, Ng T K, Zhao C, et al. True yellow light-emitting diodes as phosphor for tunable color-rendering index laser-based white light. ACS Photonics, 2016, 3, 2089 doi: 10.1021/acsphotonics.6b00457[58] Guo W, Banerjee A, Bhattacharya P, et al. InGaN/GaN disk-in-nanowire white light emitting diodes on (001) silicon. Appl Phys Lett, 2011, 98, 193102 doi: 10.1063/1.3588201[59] Lee C, Shen C, Cozzan C, et al. Gigabit-per-second white light-based visible light communication using near-ultraviolet laser diode and red-, green-, and blue-emitting phosphors. Opt Express, 2017, 25, 17480 doi: 10.1364/OE.25.017480[60] Yu F, Strempel K, Fatahilah M F, et al. Normally off vertical 3-D GaN nanowire MOSFETs with inverted p-GaN channel. IEEE Trans Electron Devices, 2018, 65, 2439 doi: 10.1109/TED.2018.2824985[61] Yin L, Du G, Liu X. Impact of ambient temperature on the self-heating effects in FinFETs. J Semicond, 2018, 39, 094011 doi: 10.1088/1674-4926/39/9/094011[62] Alfaraj N, Hussain A M, Torres Sevilla G A, et al. Functional integrity of flexible n-channel metal-oxide-semiconductor fieldeffect transistors on a reversibly bistable platform. Appl Phys Lett, 2015, 107, 174101 doi: 10.1063/1.4934355[63] Zhou X, Tan X, Wang Y, et al. Coeffect of trapping behaviors on the performance of GaN-based devices. J Semicond, 2018, 39, 094007 doi: 10.1088/1674-4926/39/9/094007[64] Zhao J, Xing Y, Fu K, et al. Influence of channel/back-barrier thickness on the breakdown of AlGaN/GaN MISHEMTs. J Semicond, 2018, 39, 094003 doi: 10.1088/1674-4926/39/9/094003[65] Mallick G, Elder R M. Graphene/hexagonal boron nitride heterostructures: Mechanical properties and fracture behavior from nanoindentation simulations. Appl Phys Lett, 2018, 113, 121902 doi: 10.1063/1.5047782[66] Zhang Z, Chen J. Thermal conductivity of nanowires. Chin Phys B, 2018, 27, 035101 doi: 10.1088/1674-1056/27/3/035101[67] Sztein A, Bowers J E, DenBaars S P, et al. Polarization field engineering of GaN/AlN/AlGaN superlattices for enhanced thermoelectric properties. Appl Phys Lett, 2014, 104, 042106 doi: 10.1063/1.4863420[68] Sztein A, Bowers J E, DenBaars S P, et al. Thermoelectric properties of lattice matched InAlN on semi-insulating GaN templates. J Appl Phys, 2012, 112, 083716 doi: 10.1063/1.4759287[69] Sztein A, Ohta H, Sonoda J, et al. GaN-based integrated lateral thermoelectric device for micro-power generation. Appl Phys Express, 2009, 2, 111003 doi: 10.1143/APEX.2.111003[70] Liu W, Balandin A A. Thermoelectric effects in wurtzite GaN and Al xGa1– xN alloys. J Appl Phys, 2005, 97, 123705 doi: 10.1063/1.1927691[71] Mark S. Lundstrom (private communication, 2017)[72] Wang D, Chen Z Y, Wang T, et al. Repeatable asymmetric resonant tunneling in AlGaN/GaN double barrier structures grown on sapphire. Appl Phys Lett, 2019, 114, 073503 doi: 10.1063/1.5080470[73] Franckié M, Bosco L, Beck M, et al. Two-well quantum cascade laser optimization by non-equilibrium Green’s function modelling. Appl Phys Lett, 2018, 112, 021104 doi: 10.1063/1.5004640[74] Andrews A M, Zederbauer T, Detz H, et al. THz quantum cascade lasers. In: Molecular Beam Epitaxy. Elsevier, 2018, 597[75] Wang F, Lee J, Phillips D J, et al. A high-efficiency regime for gas-phase terahertz lasers. Proc Natl Acad Sci USA, 2018, 115, 6614 doi: 10.1073/pnas.1803261115[76] Encomendero J, Yan R, Verma A, et al. Room temperature microwave oscillations in GaN/AlN resonant tunneling diodes with peak current densities up to 220 kA/cm2. Appl Phys Lett, 2018, 112, 103101 doi: 10.1063/1.5016414[77] Encomendero J, Faria F A, Islam S M, et al. New tunneling features in polar III-nitride resonant tunneling diodes. Phys Rev X, 2017, 7, 041017 doi: 10.1103/PhysRevX.7.041017[78] Alves T E P, Kolodziej C, Burda C, et al. Effect of particle shape and size on the morphology and optical properties of zinc oxide synthesized by the polyol method. Mater Des, 2018, 146, 125 doi: 10.1016/j.matdes.2018.03.013[79] Ghoneim M T, Sadraei A, P de Souza, et al. A protocol to characterize pH sensing materials and systems. Small Methods, 2019, 3, 1800265 doi: 10.1002/smtd.v3.2[80] Lan W, Yang Z, Zhang Y, et al. Novel transparent high-performance AgNWs/ZnO electrodes prepared on unconventional substrates with 3D structured surfaces. Appl Surf Sci, 2018, 433, 821 doi: 10.1016/j.apsusc.2017.10.054[81] Zhang B P, Binh N T, Wakatsuki K, et al. Growth of ZnO/MgZnO quantum wells on sapphire substrates and observation of the two-dimensional confinement effect. Appl Phys Lett, 2005, 86, 032105 doi: 10.1063/1.1850594[82] Maeda T, Narita T, Kanechika M, et al. Franz-Keldysh effect in GaN p–n junction diode under high reverse bias voltage. Appl Phys Lett, 2018, 112, 252104 doi: 10.1063/1.5031215[83] Maeda T, Chi X, Horita M, et al. Phonon-assisted optical absorption due to Franz-Keldysh effect in 4H-SiC p-n junction diode under high reverse bias voltage. Appl Phys Express, 2018, 11, 091302 doi: 10.7567/APEX.11.091302[84] Bridoux G, Villafuerte M, Ferreyra J M, et al. Franz-Keldysh effect in epitaxial ZnO thin films. Appl Phys Lett, 2018, 112, 092101 doi: 10.1063/1.5010942[85] Tangi M, Min J W, Priante D, et al. Observation of piezotronic and piezophototronic effects in n-InGaN nanowires/Ti grown by molecular beam epitaxy. Nano Energy, 2018, 54, 264 doi: 10.1016/j.nanoen.2018.10.031[86] Elahi H, Eugeni M, Gaudenzi P. A review on mechanisms for piezoelectric-based energy harvesters. Energies, 2018, 11, 1850 doi: 10.3390/en11071850[87] Dan M, Hu G, Li L, et al. High performance piezotronic logic nanodevices based on GaN/InN/GaN topological insulator. Nano Energy, 2018, 50, 544 doi: 10.1016/j.nanoen.2018.06.007[88] Zhu R, Yang R. Introduction to the piezotronic effect and sensing applications. In: Synthesis and Characterization of Piezotronic Materials for Application in Strain/Stress Sensing. Springer, 2018, 1[89] Zhao C, Ebaid M, Zhang H, et al. Quantified hole concentration in AlGaN nanowires for high-performance ultraviolet emitters. Nanoscale, 2018, 10, 15980 doi: 10.1039/C8NR02615G[90] Liang Y H, Towe E. Progress in efficient doping of high aluminum-containing group III-nitrides. Appl Phys Rev, 2018, 5, 011107 doi: 10.1063/1.5009349[91] Amano H, Kito M Hiramatsu K, et al. P-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation (LEEBI). Jpn J Appl Phys, 1989, 28, L2112 doi: 10.1143/JJAP.28.L2112[92] Akasaki I, Amano H, Kito M, et al. Photoluminescence of Mg-doped p-type GaN and electroluminescence of GaN p–n junction LED. J Lumin, 1991, 48, 666 doi: 10.1016/0022-2313(91)90215-H[93] Nakamura S, Senoh M, S Nagahama, et al. InGaN/GaN/AlGaN-based laser diodes with modulation-doped strained-layer superlattices grown on an epitaxially laterally overgrown GaN substrate. Appl Phys Lett, 1998, 72, 211 doi: 10.1063/1.120688[94] Nakamura S, Senoh M, Nagahama S, et al. InGaN-based multi-quantum-well-structure laser diodes. Jpn J Appl Phys, 1996, 35, L74 doi: 10.1143/JJAP.35.L74[95] Nakamura S, Mukai T, Senoh M. Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-lightemitting diodes. Appl Phys Lett, 1994, 64, 1687 doi: 10.1063/1.111832[96] Amano H, Kitoh M, Hiramatsu K, et al. Growth and luminescence properties of Mg-doped GaN prepared by MOVPE. J Electrochem Soc, 1990, 137, 1639 doi: 10.1149/1.2086742[97] Bilenko Y, Lunev A, Hu X, et al. 10 milliwatt pulse operation of 265 nm AlGaN light emitting diodes. Jpn J Appl Phys, 2004, 44(L98), L98 doi: 10.1143/jjap.44.l98[98] Bigio I J, Mourant J R. Ultraviolet and visible spectroscopies for tissue diagnostics: fluorescence spectroscopy and elastic-scattering spectroscopy. Phys Med Biol, 1997, 42, 803 doi: 10.1088/0031-9155/42/5/005[99] Hirayama H, Maeda N, Fujikawa S, et al. Recent progress and future prospects of AlGaN-based high-efficiency deep-ultraviolet light-emitting diodes. Jpn J Appl Phys, 2014, 53, 100209 doi: 10.7567/JJAP.53.100209[100] Kang B S, Wang H T, Ren F, et al. Electrical detection of biomaterials using AlGaN/GaN high electron mobility transistors. J App Phys, 2008, 104, 8 doi: 10.1063/1.2959429[101] Cho H K, Külberg A, Ploch N L, et al. Bow reduction of AlInGaN-based deep UV LED wafers using focused laser patterning. IEEE Photonics Technol Lett, 2018, 30, 1792 doi: 10.1109/LPT.2018.2869218[102] Janjua B, Priante D, Prabaswara A, et al. Ultraviolet-A LED based on quantum-disks-in-AlGaN-nanowires–Optimization and device reliability. IEEE Photonics J, 2018, 10, 2200711 doi: 10.1109/JPHOT.2018.2814482[103] SaifAddin B, Zollner C J, Almogbel A, et al. Developments in AlGaN and UVC LEDs grown on SiC. In: Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXII. Vol. 10554. International Society for Optics and Photonics, 2018, 105541E[104] Islam S M, Protasenko V, Bharadwaj S, et al Enhancing wall-plug efficiency for deep-UV light-emitting diodes: From crystal growth to devices. In: Light-Emitting Diodes. Springer, 2019, 337.[105] Wang X, Peng W, Yu R, et al. Simultaneously enhancing light emission and suppressing efficiency droop in GaN microwire-based ultraviolet light-emitting diode by the piezo-phototronic effect. Nano Lett, 2017, 17, 3718 doi: 10.1021/acs.nanolett.7b01004[106] Al Balushi Z Y, Redwing J M. In situ stress measurements during MOCVD growth of thick N-polar InGaN. J Appl Phys, 2017, 122, 085303 doi: 10.1063/1.4998745[107] Al Balushi Z Y, Redwing J M. The effect of polarity on MOCVD growth of thick InGaN. Appl Phys Lett, 2017, 110, 022101 doi: 10.1063/1.4972967[108] McLaurin M, Mates T E, Wu F, et al. Growth of p-type and n-type m-plane GaN by molecular beam epitaxy. J Appl Phys, 2006, 100, 063707 doi: 10.1063/1.2338602[109] Sugahara T, Sato H, Hao M, et al. Direct evidence that dislocations are non-radiative recombination centers in GaN. Jpn J Appl Phys, 1998, 37, L398 doi: 10.1143/JJAP.37.L398[110] Boguslawski P , Bernholc J. Doping properties of C, Si, and Ge impurities in GaN and AlN. Phys Rev B, 1997, 56, 9496 doi: 10.1103/PhysRevB.56.9496[111] Chen Z, Zhang X, Dou Z, et al. High-brightness blue light-emitting diodes enabled by a directly grown graphene buffer layer. Adv Mater, 2018, 30, 1801608 doi: 10.1002/adma.v30.30[112] Qi Y, Wang Y, Pang Z, et al. Fast growth of strain-free AlN on graphene-buffered sapphire. J Am Chem Soc, 2018, 140, 11935 doi: 10.1021/jacs.8b03871[113] Yan P, Tian Q, Yang G, et al. Epitaxial growth and interfacial property of monolayer MoS2 on gallium nitride. RSC Adv, 2018, 8, 33193 doi: 10.1039/C8RA04821E[114] Takano T, Mino T, Sakai J, et al. Deep-ultraviolet light-emitting diodes with external quantum efficiency higher than 20% at 275 nm achieved by improving light-extraction efficiency. Appl Phys Express, 2017, 10, 031002 doi: 10.7567/APEX.10.031002[115] Nam K B, Nakarmi M L, Li J, et al. Mg acceptor level in AlN probed by deep ultraviolet photoluminescence. Appl Phys Lett, 2003, 83, 878 doi: 10.1063/1.1594833[116] Van de Walle C G, Stampfl C, Neugebauer J. Theory of doping and defects in III–V nitrides. J Cryst Growth, 1998, 189/190, 505 doi: 10.1016/S0022-0248(98)00340-6[117] Kolbe T, Knauer A, Chua C, et al. Optical polarization characteristics of ultraviolet (In)(Al)GaN multiple quantum well light emitting diodes. Appl Phys Lett, 2010, 97, 171105 doi: 10.1063/1.3506585[118] Cantu P, Keller S, Mishra U K, et al. Metalorganic chemical vapor deposition of highly conductive Al0.65Ga0.35N films. Appl Phys Lett, 2003, 82, 3683 doi: 10.1063/1.1577410[119] Nam K B, Li J, Nakarmi M L, et al. Achieving highly conductive AlGaN alloys with high Al contents. Appl Phys Lett, 2002, 81, 1038 doi: 10.1063/1.1492316[120] Nippert F, Tollabi Mazraehno M, Davies M J, et al. Auger recombination in AlGaN quantum wells for UV light-emitting diodes. Appl Phys Lett, 2018, 113, 071107 doi: 10.1063/1.5044383[121] Kioupakis E, Rinke P, Delaney K T, et al. Indirect Auger recombination as a cause of efficiency droop in nitride light-emitting diodes. Appl Phys Lett, 2011, 98, 161107 doi: 10.1063/1.3570656[122] Zhang M, Bhattacharya P, Singh J, et al. Direct measurement of auger recombination in In0.1Ga0.9N/GaN quantum wells and its impact on the efficiency of In0.1Ga0.9N/GaN multiple quantum well light emitting diodes. Appl Phys Lett, 2009, 95, 201108 doi: 10.1063/1.3266520[123] Shen Y C, Mueller G O, Watanabe S, et al. Auger recombination in InGaN measured by photoluminescence. Appl Phys Lett, 2007, 91, 141101 doi: 10.1063/1.2785135[124] Yun J, Shim J I, Hirayama H. Analysis of efficiency droop in 280-nm AlGaN multiple-quantum-well light-emitting diodes based on carrier rate equation. Appl Phys Express, 2015, 8, 022104 doi: 10.7567/APEX.8.022104[125] Dreyer C E, Alkauskas A, Lyons J L, et al. Gallium vacancy complexes as a cause of Shockley-Read-Hall recombination in III-nitride light emitters. Appl Phys Lett, 2016, 108, 141101 doi: 10.1063/1.4942674[126] Karpov S Y, Makarov Y N. Dislocation effect on light emission efficiency in gallium nitride. Appl Phys Lett, 2002, 81, 4721 doi: 10.1063/1.1527225[127] Nagasawa Y, Hirano A. A review of AlGaN-based deep-ultraviolet light-emitting diodes on sapphire. Appl Sci, 2018, 8, 1264 doi: 10.3390/app8081264[128] Hakamata J, Kawase Y, Dong L, et al. Growth of high-quality AlN and AlGaN films on sputtered AlN/sapphire templates via high-temperature annealing. Phys Status Solidi B, 2018, 255, 1700506 doi: 10.1002/pssb.v255.5[129] Nakamura S, Mukai T, Senoh M, et al. Thermal annealing effects on p-type Mg-doped GaN films. Jpn J Appl Phys, 1992, 31, L139 doi: 10.1143/JJAP.31.L139[130] Liang F, Yang J, Zhao D G, et al. Resistivity reduction of low temperature grown p-Al0.09Ga0.91N by suppressing the incorporation of carbon impurity. AIP Adv, 2018, 8, 085005 doi: 10.1063/1.5046875[131] Hömmerich U, Nyein E E, Lee D, et al. Photoluminescence studies of rare earth (Er, Eu, Tm) in situ doped GaN. Mater Sci Eng B, 2003, 105, 91 doi: 10.1016/j.mseb.2003.08.022[132] Chen M T, Lu M P, Wu Y J, et al. Near UV LEDs made with in situ doped p-n homojunction ZnO nanowire arrays. Nano Lett, 2010, 10, 4387 doi: 10.1021/nl101907h[133] Derluyn J, Boeykens S, Cheng K, et al. Improvement of AlGaN/GaN high electron mobility transistor structures by in situ deposition of a Si3N4 surface layer. J Appl Phys, 2005, 98, 054501 doi: 10.1063/1.2008388[134] Fujiwara H, Sasaki K. Amplified spontaneous emission from a surface-modified GaN film fabricated under pulsed intense UV laser irradiation. Appl Phys Lett, 2018, 113, 171606 doi: 10.1063/1.5040551[135] Ng T K, Yan J. Special section guest editorial: Semiconductor UV photonics. J Nanophotonics, 2018, 12, 043501 doi: 10.1117/1.JNP.12.043501[136] Guo Y, Yan J, Zhang Y, et al. Enhancing the light extraction of AlGaN-based ultraviolet light-emitting diodes in the nanoscale. J Nanophotonics, 2018, 12, 043510 doi: 10.1063/1.4991664[137] Alias M S, Tangi M, Holguin-Lerma J A, et al. Review of nanophotonics approaches using nanostructures and nanofabrication for III-nitrides ultraviolet-photonic devices. J Nanophotonics, 2018, 12, 043508 doi: 10.1117/1.JNP.12.043508[138] Min J W, Priante D, Tangi M, et al. Unleashing the potential of molecular beam epitaxy grown AlGaN-based ultraviolet-spectrum nanowires devices. J Nanophotonics, 2018, 12, 043511 doi: 10.1117/1.JNP.12.043511[139] Sun J, Lu C, Song Y, et al. Recent progress in the tailored growth of two-dimensional hexagonal boron nitride via chemical vapour deposition. Chem Soc Rev, 2018, 47, 4242 doi: 10.1039/C8CS00167G[140] Jiang H X, Lin J Y. Hexagonal boron nitride for deep ultraviolet photonic devices. Semicond Sci Technol, 2014, 29, 084003 doi: 10.1088/0268-1242/29/8/084003[141] Giovannetti G, Khomyakov P A, Brocks G, et al. Substrate-induced band gap in graphene on hexagonal boron nitride: Ab initio density functional calculations. Phys Rev B, 2007, 76, 073103 doi: 10.1103/PhysRevB.76.073103[142] Kang C H, Shen C, Saheed M S M, et al. Carbon nanotubegraphene composite film as transparent conductive electrode for GaN-based light-emitting diodes. Appl Phys Lett, 2016, 109, 081902 doi: 10.1063/1.4961667[143] Tangi M, Shakfa M K, Mishra P, et al. Anomalous photoluminescence thermal quenching of sandwiched single layer MoS2. Opt Mater Express, 2017, 7, 3697 doi: 10.1364/OME.7.003697[144] Mak K F, He K, Lee C, et al. Tightly bound trions in monolayer MoS2. Nat Mater, 2013, 12, 207 doi: 10.1038/nmat3505[145] Tadjer M J, Koehler A D, Freitas J A, et al. High resistivity halide vapor phase homoepitaxial β-Ga2O3 films Co-doped by silicon and nitrogen. Appl Phys Lett, 2018, 113, 192102 doi: 10.1063/1.5045601[146] Li W, Zhao X, Zhi Y, et al. Fabrication of cerium-doped β-Ga2O3 epitaxial thin films and deep ultraviolet photodetectors. Appl Opt, 2018, 57, 538 doi: 10.1364/AO.57.000538[147] Higashiwaki M, Jessen G H. The dawn of gallium oxide microelectronics. Appl Phys Lett, 2018, 112, 060401 doi: 10.1063/1.5017845[148] Peelaers H, Varley J B, Speck J S, et al. Structural and electronic properties of Ga2O3–Al2O3 alloys. Appl Phys Lett, 2018, 112, 242101 doi: 10.1063/1.5036991[149] Pearton S J, Yang J, Cary I V P H , et al. A review of Ga2O3 materials, processing, and devices. Appl Phys Rev, 2018, 5, 011301 doi: 10.1063/1.5006941[150] Yang T H, Fu H, Chen H, et al. Temperature-dependent electrical properties of β-Ga2O3 Schottky barrier diodes on highly doped single-crystal substrates. J Semicond, 2019, 40, 012801 doi: 10.1088/1674-4926/40/1/012801[151] Lu X, Zhou L, Chen L, et al. X-ray detection performance of vertical Schottky photodiodes based on a bulk β-Ga2O3 substrate grown by an EFG method. ECS J Solid State Sci Technol, 2019, 8, Q3046 doi: 10.1149/2.0071907jss[152] Cheng Z, Hanke M, Galazka Z, et al. Thermal expansion of single-crystalline β-Ga2O3 from RT to 1200 K studied by synchrotron-based high resolution x-ray diffraction. Appl Phys Lett, 2018, 113, 182102 doi: 10.1063/1.5054265[153] Katre A, Carrete J, Wang T, et al. Phonon transport unveils the prevalent point defects in GaN. Phys Rev Mater, 2018, 2, 050602 doi: 10.1103/PhysRevMaterials.2.050602[154] Imura M, Ota Y, Banal R G, Liao M, et al. Effect of boron incorporation on structural and optical properties of AlN layers grown by metalorganic vapor phase epitaxy. Phys Status Solidi A, 2018, 215(21), 1800282 doi: 10.1002/pssa.201800282[155] Kojima K, Takashima S, Edo M, et al. Nitrogen vacancies as a common element of the green luminescence and nonradiative recombination centers in Mg-implanted GaN layers formed on a GaN substrate. Appl Phys Express, 2017, 10, 061002 doi: 10.7567/APEX.10.061002[156] Kamimura J, Bogdanoff P, Ramsteiner M, et al. p-type doping of GaN nanowires characterized by photoelectrochemical measurements. Nano Lett, 2017, 17, 1529 doi: 10.1021/acs.nanolett.6b04560[157] Pavesi M, Manfredi M, Salviati G, et al. Optical evidence of an electrothermal degradation of InGaN-based light-emitting diodes during electrical stress. Appl Phys Lett, 2004, 84, 3403 doi: 10.1063/1.1734682[158] Reboredo F A, Pantelides S T. Novel defect complexes and their role in the p-type doping of GaN. Phys Rev Lett, 1999, 82, 1887 doi: 10.1103/PhysRevLett.82.1887[159] Miceli G, Pasquarello A. Self-compensation due to point defects in Mg-doped GaN. Phys Rev B, 2016, 93, 165207 doi: 10.1103/PhysRevB.93.165207[160] Dai Q, Zhang X, Wu Z, et al. Effects of Mg-doping on characteristics of semi-polar ($ 11\bar 22$ ) plane p-AlGaN films. Mater Lett, 2017, 209, 472 doi: 10.1016/j.matlet.2017.08.091[161] Pampili P, Parbrook P J. Doping of III-nitride materials. Mater Sci Semicond Process, 2017, 62, 180 doi: 10.1016/j.mssp.2016.11.006[162] Taniyasu Y, Kasu M, Makimoto T. An aluminium nitride light-emitting diode with a wavelength of 210 nanometres. Nature, 2006, 441, 325 doi: 10.1038/nature04760[163] Taniyasu Y, Kasu M, Kobayashi N. Intentional control of n-type conduction for Si-doped AlN and Al xGa1– xN (0.42 ≤ x < 1). Appl Phys Lett, 2002, 81, 1255 doi: 10.1063/1.1499738[164] Nakarmi M L, Kim K H, Zhu K, et al. Transport properties of highly conductive n-type Alrich Al xGa1– xN (x ≥ 0.7). Appl Phys Lett, 2004, 85, 3769 doi: 10.1063/1.1809272[165] Collazo R, Mita S, Xie J, et al. Progress on n-type doping of AlGaN alloys on AlN single crystal substrates for UV optoelectronic applications. Phys Status Solidi C, 2011, 8, 2031 doi: 10.1002/pssc.v8.7/8[166] Mehnke F, Wernicke T, Pingel H, et al. Highly conductive n-Al xGa1– xN layers with aluminum mole fractions above 80%. Appl Phys Lett, 2013, 103, 212109 doi: 10.1063/1.4833247[167] Nakarmi M L, Nepal N, Ugolini C, et al. Correlation between optical and electrical properties of Mg-doped AlN epilayers. Appl Phys Lett, 2006, 89, 152120 doi: 10.1063/1.2362582[168] Mireles F, Ulloa S E. Acceptor binding energies in GaN and AlN. Phys Rev B, 1998, 58, 3879 doi: 10.1103/PhysRevB.58.3879[169] Li J, Oder T N, Nakarmi M L, et al. Optical and electrical properties of Mg-doped p-type Al xGa1– xN. Appl Phys Lett, 2002, 80, 1210 doi: 10.1063/1.1450038[170] Sarwar A T M G, May B J, Deitz J I, et al. Tunnel junction enhanced nanowire ultraviolet light emitting diodes. Appl Phys Lett, 2015, 107, 101103 doi: 10.1063/1.4930593[171] Kaneko M, Ueta S, Horita M, et al. Deep-ultraviolet light emission from 4H-AlN/4H-GaN short-period superlattice grown on 4H-SiC($ 11\bar 20$ ). Appl Phys Lett, 2018, 112, 012106 doi: 10.1063/1.5006435[172] Liu S, Ye C, Cai X, et al. Performance enhancement of AlGaN deep-ultraviolet light-emitting diodes with varied superlattice barrier electron blocking layer. Appl Phys A, 2016, 122, 527 doi: 10.1007/s00339-016-0073-0[173] Kozodoy P, Hansen M, DenBaars S P, et al. Enhanced Mg doping efficiency in Al0.2Ga0.8N/GaN superlattices. Appl Phys Lett, 1999, 74, 3681 doi: 10.1063/1.123220[174] Sun H, Yin J, Pecora E F, et al. Deep-ultraviolet emitting AlGaN multiple quantum well graded-index separate-confinement heterostructures grown by MBE on SiC substrates. IEEE Photon J, 2017, 9, 2201109 doi: 10.1109/JPHOT.2017.2716420[175] Sun H, Pecora E F, Woodward J, et al. Effect of indium in Al0.65Ga0.35N/Al0.8Ga0.2N MQWs for the development of deep-UV laser structures in the form of graded-index separate confinement heterostructure (GRINSCH). Phys Status Solidi A, 2016, 213, 1165 doi: 10.1002/pssa.v213.5[176] Sun H, Woodward J, Yin J, et al. Development of AlGaN-based graded-index-separate-confinement-heterostructure deep UV emitters by molecular beam epitaxy. J Vac Sci Technol B, 2013, 31, 03C117 doi: 10.1116/1.4796107[177] Sun H, Moustakas T D. UV emitters based on an AlGaN p-n junction in the form of graded-index separate confinement heterostructure. Appl Phys Express, 2013, 7, 012104 doi: 10.7567/APEX.7.012104[178] Simon J, Protasenko V, Lian C, et al. Polarization-induced hole doping in wide-band-gap uniaxial semiconductor heterostructures. Science, 2010, 327, 60 doi: 10.1126/science.1183226[179] Liu C, Ooi Y K, Islam S M, et al. Physics and polarization characteristics of 298 nm AlN-delta-GaN quantum well ultraviolet light-emitting diodes. Appl Phys Lett, 2017, 110, 071103 doi: 10.1063/1.4976203[180] Nakarmi M L, Kim K H, Li J, et al. Enhanced p-type conduction in GaN and AlGaN by Mg-δ-doping. Appl Phys Lett, 2003, 82, 3041 doi: 10.1063/1.1559444[181] Gaddy B E, Bryan Z, Bryan I, et al. The role of the carbon-silicon complex in eliminating deep ultraviolet absorption in AlN. Appl Phys Lett, 2014, 104, 202106 doi: 10.1063/1.4878657[182] Wu H, Zheng R, Liu W, et al. C and Si codoping method for p-type AlN. J Appl Phys, 2010, 108, 053715 doi: 10.1063/1.3475708[183] Tran N H, Le B H, Zhao S, et al. On the mechanism of highly efficient p-type conduction of Mg-doped ultra-widebandgap AlN nanostructures. Appl Phys Lett, 2017, 110, 032102 doi: 10.1063/1.4973999[184] Connie A T, Zhao S, Sadaf S M, et al. Optical and electrical properties of Mg-doped AlN nanowires grown by molecular beam epitaxy. Appl Phys Lett, 2015, 106, 213105 doi: 10.1063/1.4921626[185] Sedhain A, Al Tahtamouni T M, Li J, et al. Beryllium acceptor binding energy in AlN. Appl Phys Lett, 2008, 93, 141104 doi: 10.1063/1.2996977[186] Wu R, Shen L, Yang M, et al. Possible efficient p-type doping of AlN using Be: An ab initio study. Appl Phys Lett, 2007, 91, 152110 doi: 10.1063/1.2799241[187] Szabó Á, Son N T, Janzén E, et al. Group-II acceptors in wurtzite AlN: A screened hybrid density functional study. Appl Phys Lett, 2010, 96, 192110 doi: 10.1063/1.3429086[188] Soltamov V A, Rabchinskii M K, Yavkin B V, et al. Properties of AlN single crystals doped with Beryllium via high temperature diffusion. Appl Phys Lett, 2018, 113, 082104 doi: 10.1063/1.5043175[189] Wang Q, Bowen C R, Lewis R, et al. Hexagonal boron nitride nanosheets doped pyroelectric ceramic composite for high-performance thermal energy harvesting. Nano Energy, 2019, 60, 144 doi: 10.1016/j.nanoen.2019.03.037[190] Puchta R. A brighter beryllium. Nat Chem, 2011, 3, 416 doi: 10.1038/nchem.1033[191] Park J H, Kim D Y, Schubert E F, et al. Fundamental limitations of wide-bandgap semiconductors for light-emitting diodes. ACS Energy Lett, 2018, 3, 655 doi: 10.1021/acsenergylett.8b00002[192] Kamiyama S, Iwaya M, Hayashi N, et al. Low-temperature-deposited AlGaN interlayer for improvement of AlGaN/GaN heterostructure. J Cryst Growth, 2001, 223, 83 doi: 10.1016/S0022-0248(00)01017-4[193] Islam S M, Lee K, Verma J, et al. MBE-grown 232–270 nm deep-UV LEDs using monolayer thin binary GaN/AlN quantum heterostructures. Appl Phys Lett, 2017, 110, 041108 doi: 10.1063/1.4975068[194] Wang L Y, Song W D, Hu W X, et al. Efficiency enhancement of ultraviolet light-emitting diodes with segmentally graded p-type AlGaN layer. Chin Phys B, 2019, 28, 018503 doi: 10.1088/1674-1056/28/1/018503[195] Strak P, Kempisty P, Ptasinska M, et al. Principal physical properties of GaN/AlN multiquantum well systems determined by density functional theory calculations. J Appl Phys, 2013, 113, 193706 doi: 10.1063/1.4805057[196] Long H, Wang S, Dai J, et al. Internal strain induced significant enhancement of deep ultraviolet light extraction efficiency for AlGaN multiple quantum wells grown by MOCVD. Opt Express, 2018, 26, 680 doi: 10.1364/OE.26.000680[197] Reich C, Guttmann M, Feneberg M, et al. Strongly transverse-electric-polarized emission from deep ultraviolet AlGaN quantum well light emitting diodes. Appl Phys Lett, 2015, 107, 142101 doi: 10.1063/1.4932651[198] Verma J, Islam S M, Protasenko V, et al. Tunnel-injection quantum dot deep-ultraviolet light-emitting diodes with polarization-induced doping in III-nitride heterostructures. Appl Phys Lett, 2014, 104, 021105 doi: 10.1063/1.4862064[199] Verma J, Kandaswamy P K, Protasenko V, et al. Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes. Appl Phys Lett, 2013, 102, 041103 doi: 10.1063/1.4789512[200] Taniyasu Y, Kasu M. Polarization property of deepultraviolet light emission from C-plane AlN/GaN short-period superlattices. Appl Phys Lett, 2011, 99, 251112 doi: 10.1063/1.3671668[201] Zhao S, Mi Z. Al(Ga)N nanowire deep ultraviolet optoelectronics. Semicond Semimet, 2017, 96, 167[202] Beeler M, Hille P, Schormann J, et al. Intraband absorption in self-assembled Ge-doped GaN/AlN nanowire heterostructures. Nano Lett, 2014, 14, 1665 doi: 10.1021/nl5002247[203] Tchernycheva M, Nevou L, Doyennette L, et al. Systematic experimental and theoretical investigation of intersubband absorption in GaN/AlN quantum wells. Phys Rev B, 2006, 73, 125347 doi: 10.1103/PhysRevB.73.125347[204] Cociorva D, Aulbur W G, Wilkins J W. Quasiparticle calculations of band offsets at AlN–GaN interfaces. Solid State Commun, 2002, 124, 63 doi: 10.1016/S0038-1098(02)00326-5[205] Binggeli N, Ferrara P, Baldereschi A. Band-offset trends in nitride heterojunctions. Phys Rev B, 2001, 63, 245306 doi: 10.1103/PhysRevB.63.245306[206] Kamiya K, Ebihara Y, Kasu M, . Efficient structure for deep-ultraviolet light-emitting diodes with high emission efficiency: A first-principles study of AlN/GaN superlattice. Jpn J Appl Phys, 2012, 51, 02BJ11 doi: 10.7567/JJAP.51.02BJ11[207] Bayerl D, Islam S M, Jones C M, et al. Deep ultraviolet emission from ultra-thin GaN/AlN heterostructures. Appl Phys Lett, 2016, 109, 241102 doi: 10.1063/1.4971968[208] Islam S M, Protasenko V, Rouvimov S, et al. Sub-230 nm deep-UV emission from GaN quantum disks in AlN grown by a modified Stranski-Krastanov mode. Jpn J Appl Phys, 2016, 55, 05FF06 doi: 10.7567/JJAP.55.05FF06[209] Bayerl D, Kioupakis E. Visible-wavelength polarized-light emission with small-diameter InN nanowires. Nano Lett, 2014, 14, 3709 doi: 10.1021/nl404414r[210] Efros A L, Delehanty J B, Huston A L, et al. Evaluating the potential of using quantum dots for monitoring electrical signals in neurons. Nat Nanotechnol, 2018, 13, 278 doi: 10.1038/s41565-018-0107-1[211] Sharma A S, Dhar S. Dependence of strain distribution on In content in InGaN/GaN quantum wires and spherical quantum dots. J Electron Mater, 2018, 47, 1239 doi: 10.1007/s11664-017-5900-3[212] Renard J, Kandaswamy P K, Monroy E, et al. Suppression of nonradiative processes in long-lived polar GaN/AlN quantum dots. Appl Phys Lett, 2009, 95, 131903 doi: 10.1063/1.3238311[213] Janjua B, Sun H, Zhao C, et al. Self-planarized quantum-disks-in-nanowires ultraviolet-B emitters utilizing pendeo-epitaxy. Nanoscale, 2017, 9, 7805 doi: 10.1039/C7NR00006E[214] Zhao C, Ng T K, Wei N, et al. Facile formation of high-quality InGaN/GaN quantum-disks-in-nanowires on bulk-metal substrates for high-power light-emitters. Nano Lett, 2016, 16, 1056 doi: 10.1021/acs.nanolett.5b04190[215] Hestroffer K, Leclere C, Cantelli V, et al. In situ study of self-assembled GaN nanowires nucleation on Si(111) by plasma-assisted molecular beam epitaxy. Appl Phys Lett, 2012, 100, 212107 doi: 10.1063/1.4721521[216] Schumann T, Gotschke T, Limbach F, et al. Selective-area catalyst-free MBE growth of GaN nanowires using a patterned oxide layer. Nanotechnology, 2011, 22, 095603 doi: 10.1088/0957-4484/22/9/095603[217] Ravi L, Boopathi K, Panigrahi P, et al. Growth of gallium nitride nanowires on sapphire and silicon by chemical vapor deposition for water splitting applications. Appl Surf Sci, 2018, 449, 213 doi: 10.1016/j.apsusc.2018.01.306[218] Fan S, Zhao S, Chowdhury F A, et al. Molecular beam epitaxial growth of III-nitride nanowire heterostructures and emerging device applications. In: Handbook of GaN Semiconductor Materials and Devices. CRC Press, 2017, 265[219] Heilmann M, Munshi A M, Sarau G, et al. Vertically oriented growth of GaN nanorods on Si using graphene as an atomically thin buffer layer. Nano Lett, 2016, 16, 3524 doi: 10.1021/acs.nanolett.6b00484[220] Zhong Z, Qian F, Wang D, et al. Synthesis of p-type gallium nitride nanowires for electronic and photonic nanodevices. Nano Lett, 2003, 3, 343 doi: 10.1021/nl034003w[221] Wang R, Nguyen H P T, Connie A T, et al. Color-tunable, phosphor-free InGaN nanowire light-emitting diode arrays monolithically integrated on silicon. Opt Express, 2014, 22, A1768 doi: 10.1364/OE.22.0A1768[222] Parkinson P, Joyce H J, Gao Q, et al. Carrier lifetime and mobility enhancement in nearly defect-free core- shell nanowires measured using time-resolved terahertz spectroscopy. Nano Lett, 2009, 9, 3349 doi: 10.1021/nl9016336[223] Tham D, Nam C Y, Fischer J E. Defects in GaN nanowires. Adv Funct Mater, 2006, 16, 1197 doi: 10.1002/(ISSN)1616-3028[224] Le B H, Zhao S, Liu X, et al. Controlled coalescence of AlGaN nanowire arrays: An architecture for nearly dislocation-free planar ultraviolet photonic device applications. Adv Mater, 2016, 28, 8446 doi: 10.1002/adma.201602645[225] Chang Y L, Wang J, Li F, et al. High efficiency green, yellow, and amber emission from InGaN/GaN dot-in-a-wire heterostructures on Si(111). Appl Phys Lett, 2010, 96, 013106 doi: 10.1063/1.3284660[226] Yan R, Gargas D, Yang P. Nanowire photonics. Nat Photonics, 2009, 3, 569 doi: 10.1038/nphoton.2009.184[227] Qian F, Gradecak S, Li Y, et al. Core/multishell nanowire heterostructures as multicolor, high-efficiency light-emitting diodes. Nano Lett, 2005, 5, 2287 doi: 10.1021/nl051689e[228] Qian F, Li Y, Gradecak S, et al. Gallium nitride-based nanowire radial heterostructures for nanophotonics. Nano Lett, 2004, 4, 1975 doi: 10.1021/nl0487774[229] Priante D, Tangi M, Min J W, et al. Enhanced electro-optic performance of surface-treated nanowires: origin and mechanism of nanoscale current injection for reliable ultraviolet light-emitting diodes. Opt Mater Express, 2019, 9, 203 doi: 10.1364/OME.9.000203[230] Almutlaq J, Yin J, Mohammed O F, et al. The benefit and challenges of zero-dimensional perovskites. J Phys Chem Lett, 2018, 9, 4131 doi: 10.1021/acs.jpclett.8b00532[231] Hung N T, Hasdeo E H, Nugraha A R, et al. Quantum effects in the thermoelectric power factor of low-dimensional semiconductors. Phys Rev Lett, 2016, 117, 036602 doi: 10.1103/PhysRevLett.117.036602[232] Li H, Geelhaar L, Riechert H, et al. Computing equilibrium shapes of wurtzite crystals: The example of GaN. Phys Rev Lett, 2015, 115, 085503 doi: 10.1103/PhysRevLett.115.085503[233] Schuster F, Winnerl A, Weiszer S, et al. Doped GaN nanowires on diamond: Structural properties and charge carrier distribution. J Appl Phys, 2015, 117, 044307 doi: 10.1063/1.4906747[234] Nguyen H P T, Djavid M, Cui K, et al. Temperature-dependent nonradiative recombination processes in GaN-based nanowire white-light-emitting diodes on silicon. Nanotechnology, 2012, 23, 194012 doi: 10.1088/0957-4484/23/19/194012[235] Moustakas T D. Ultraviolet optoelectronic devices based on AlGaN alloys grown by molecular beam epitaxy. MRS Commun, 2016, 6, 247 doi: 10.1557/mrc.2016.26[236] Liu K, Sun H, AlQatari F, et al. Wurtzite BAlN and BGaN alloys for heterointerface polarization engineering. Appl Phys Lett, 2017, 111, 222106 doi: 10.1063/1.5008451[237] Li X, Wang S, Liu H, et al. 100-nm thick single-phase wurtzite BAlN films with boron contents over 10%. Phys Status Solidi B, 2017, 254, 1600699 doi: 10.1002/pssb.v254.8[238] Orsal G, Maloufi N, Gautier S, et al. Effect of boron incorporation on growth behavior of BGaN/GaN by MOVPE. J Cryst Growth, 2008, 310, 5058 doi: 10.1016/j.jcrysgro.2008.08.024[239] Escalanti L, Hart G L W. Boron alloying in GaN. Appl Phys Lett, 2004, 84, 705 doi: 10.1063/1.1644910[240] Teles L K, Furthmüller J, Scolfaro L M R, et al. Phase separation and gap bowing in zinc-blende InGaN, InAlN, BGaN, and BAlN alloy layers. Physica E, 2002, 13, 1086 doi: 10.1016/S1386-9477(02)00309-0[241] Teles L K, Scolfaro L M R, Leite J R, et al. Spinodal decomposition in B xGa1– xN and B xAl1– xN alloys. Appl Phys Lett, 2002, 80, 1177 doi: 10.1063/1.1450261[242] Edgar J H, Smith D T, Eddy C R Jr, et al. c-Boron-aluminum nitride alloys prepared by ion-beam assisted deposition. Thin Solid Films, 1997, 298, 33 doi: 10.1016/S0040-6090(96)08884-0[243] Jiang H X, Lin J Y. Hexagonal boron nitride epilayers: Growth, optical properties and device applications. ECS J Solid State Sci Technol, 2017, 6, Q3012 doi: 10.1149/2.0031702jss[244] Das T, Chakrabarty S, Kawazoe Y, et al. Tuning the electronic and magnetic properties of graphene/h-BN hetero nanoribbon: A first-principles investigation. AIP Adv, 2018, 8, 065111 doi: 10.1063/1.5030374[245] Kubota Y, Watanabe K, Tsuda O, et al. Deep ultraviolet light-emitting hexagonal boron nitride synthesized at atmospheric pressure. Science, 2007, 317, 932 doi: 10.1126/science.1144216[246] Blase X, Rubio A, Louie S G, et al. Quasiparticle band structure of bulk hexagonal boron nitride and related systems. Phys Rev B, 1995, 51, 6868 doi: 10.1103/PhysRevB.51.6868[247] Rubio A, Corkill J L, Cohen M L. Theory of graphitic boron nitride nanotubes. Phys Rev B, 1994, 49, 5081 doi: 10.1103/PhysRevB.49.5081[248] Arnaud B, Lebegue S, Rabiller P, et al. Huge excitonic effects in layered hexagonal boron nitride. Phys Rev Lett, 2006, 96, 026402 doi: 10.1103/PhysRevLett.96.026402[249] Hong X, Wang D, Chung D D L. Boron nitride nanotube mat as a low-k dielectric material with relative dielectric constant ranging from 1.0 to 1.1. J Electron Mater, 2016, 45, 453 doi: 10.1007/s11664-015-4123-8[250] Yin J, Li J, Hang Y, et al. Boron nitride nanostructures: Fabrication, functionalization and applications. Small, 2016, 12, 2942 doi: 10.1002/smll.201600053[251] Shehzad K, Xu Y, Gao C, et al. Three-dimensional macro-structures of two-dimensional nanomaterials. Chem Soc Rev, 2016, 45, 5541 doi: 10.1039/C6CS00218H[252] Terao T, Zhi C, Bando Y, et al. Alignment of boron nitride nanotubes in polymeric composite films for thermal conductivity improvement. J Phys Chem C, 2010, 114, 4340 doi: 10.1021/jp911431f[253] Zhi C, Bando Y, Tang C, et al. Boron nitride nanotubes. Mater Sci Eng R, 2010, 70, 92 doi: 10.1016/j.mser.2010.06.004[254] Henck H, Pierucci D, Fugallo G, et al. Direct observation of the band structure in bulk hexagonal boron nitride. Phys Rev B, 2017, 95, 085410 doi: 10.1103/PhysRevB.95.085410[255] Grenadier S J, Maity A, Li J, et al. Origin and roles of oxygen impurities in hexagonal boron nitride epilayers. Appl Phys Lett, 2018, 112, 162103 doi: 10.1063/1.5026291[256] Du X Z, Li J, Lin J Y, et al. The origins of near band-edge transitions in hexagonal boron nitride epilayers. Appl Phys Lett, 2016, 108, 052106 doi: 10.1063/1.4941540[257] Attaccalite C, Bockstedte M, Marini A, et al. Coupling of excitons and defect states in boron-nitride nanostructures. Phys Rev B, 2011, 83, 144115 doi: 10.1103/PhysRevB.83.144115[258] Schué L, Sponza L, Plaud A, et al. Bright luminescence from indirect and strongly bound excitons in h-BN. Phys Rev Lett, 2019, 122, 067401 doi: 10.1103/PhysRevLett.122.067401[259] Watanabe K, Taniguchi T. Jahn-Teller effect on exciton states in hexagonal boron nitride single crystal. Phys Rev B, 2009, 79, 193104 doi: 10.1103/PhysRevB.79.193104[260] Watanabe K, Taniguchi T, Kanda H. Direct-bandgap properties and evidence for ultraviolet lasing of hexagonal boron nitride single crystal. Nat Mater, 2004, 3, 404 doi: 10.1038/nmat1134[261] Solozhenko V L, Lazarenko A G, Petitet J P, et al. Bandgap energy of graphite-like hexagonal boron nitride. J Phys Chem Solids, 2001, 62, 1331 doi: 10.1016/S0022-3697(01)00030-0[262] Carlisle J A, Shirley E L, Terminello L J, et al. Band-structure and core-hole effects in resonant inelastic softx-ray scattering: Experiment and theory. Phys Rev B, 1999, 59, 7433 doi: 10.1103/PhysRevB.59.7433[263] Jia J J, Callcott T A, Shirley E L, et al. Resonant inelastic X-ray scattering in hexagonal boron nitride observed by soft-X-ray fluorescence spectroscopy. Phys Rev Lett, 1996, 76, 4054 doi: 10.1103/PhysRevLett.76.4054[264] Taylor C A, Brown S W, Subramaniam V, et al. Observation of near-band-gap luminescence from boron nitride films. Appl Phys Lett, 1994, 65, 1251 doi: 10.1063/1.112086[265] Lopatin V V, Konusov F V. Energetic states in the boron nitride band gap. J Phys Chem Solids, 1992, 53, 847 doi: 10.1016/0022-3697(92)90199-N[266] Tarrio C, Schnatterly S E. Interband transitions, plasmons, and dispersion in hexagonal boron nitride. Phys Rev B, 1989, 40, 7852 doi: 10.1103/PhysRevB.40.7852[267] Hoffman D M, Doll G L, Eklund P C. Optical properties of pyrolytic boron nitride in the energy range 0.05–10 eV. Phys Rev B, 1984, 30, 6051 doi: 10.1103/PhysRevB.30.6051[268] Sugino T, Tanioka K, Kawasaki S, et al. Characterization and field emission of sulfur-doped boron nitride synthesized by plasma-assisted chemical vapor deposition. Jpn J Appl Phys, 1997, 36, L463 doi: 10.1143/JJAP.36.L463[269] Carpenter L G, Kirby P J. The electrical resistivity of boron nitride over the temperature range 700 °C to 1400 °C. J Phys D, 1982, 15, 1143 doi: 10.1088/0022-3727/15/7/009[270] Davies B M, Bassani F, Brown F C, et al. Core excitons at the boron K edge in hexagonal BN. Phys Rev B, 1981, 24, 3537 doi: 10.1103/PhysRevB.24.3537[271] Tegeler E, Kosuch N, Wiech G, et al. On the electronic structure of hexagonal boron nitride. Phys Status Solidi B, 1979, 91, 223 doi: 10.1002/(ISSN)1521-3951[272] Zunger A, Katzir A, Halperin A. Optical properties of hexagonal boron nitride. Phys Rev B, 1976, 13, 5560 doi: 10.1103/PhysRevB.13.5560[273] Brown F C, Bachrach R Z, Skibowski M. Effect of X-ray polarization at the boron K edge in hexagonal BN. Phys Rev B, 1976, 13, 2633 doi: 10.1103/PhysRevB.13.2633[274] Zupan J, Kolar D. Optical properties of graphite and boron nitride. J Phys C Solid State Phys, 1972, 5, 3097 doi: 10.1088/0022-3719/5/21/014[275] Cassabois G, Valvin P, Gil B. Hexagonal boron nitride is an indirect bandgap semiconductor. Nat Photonics, 2016, 10, 262 doi: 10.1038/nphoton.2015.277[276] Laleyan D A, Zhao S, Woo S Y, et al. AlN/h-BN heterostructures for Mg dopant-free deep ultraviolet photonics. Nano Lett, 2017, 17, 3738 doi: 10.1021/acs.nanolett.7b01068[277] Cadiz F, Courtade E, Robert C, et al. Excitonic linewidth approaching the homogeneous limit in MoS2-based van der Waals heterostructures. Phys Rev X, 2017, 7, 021026 doi: 10.1103/PhysRevX.7.021026[278] Museur L, Brasse G, Pierret A, et al. Exciton optical transitions in a hexagonal boron nitride single crystal. Phys Status Solidi RRL, 2011, 5, 214 doi: 10.1002/pssr.v5.5/6[279] Pierucci D, Zribi J, Henck H, et al. Van der Waals epitaxy of two-dimensional single-layer h-BN on graphite by molecular beam epitaxy: Electronic properties and band structure. Appl Phys Lett, 2018, 112, 253102 doi: 10.1063/1.5029220[280] Schubert E F. Light-emitting diodes. Cambridge University Press, 2006[281] Kaneko K, Fujita S, Hitora T. A power device material of corundum-structured α-Ga2O3 fabricated by MIST EPITAXY® technique. Jpn J Appl Phys, 2018, 57, 02CB18 doi: 10.7567/JJAP.57.02CB18[282] Fujita S, Oda M, Kaneko K, et al. Evolution of corundum-structured III-oxide semiconductors: Growth, properties, and devices. Jpn J Appl Phys, 2016, 55, 1202A3 doi: 10.7567/JJAP.55.1202A3[283] Shinohara D, Fujita S. Heteroepitaxy of corundum-structured α-Ga2O3 thin films on α-Al2O3 substrates by ultrasonic mist chemical vapor deposition. Jpn J Appl Phys, 2008, 47, 7311 doi: 10.1143/JJAP.47.7311[284] Marezio M, Remeika J P. Bond lengths in the α-Ga2O3 structure and the high-pressure phase of Ga2– xFe xO3. J Chem Phys, 1967, 46, 1862 doi: 10.1063/1.1840945[285] Leszczynski M, Teisseyre H, Suski T, et al. Lattice parameters of gallium nitride. Appl Phys Lett, 1996, 69, 73 doi: 10.1063/1.118123[286] Zhao J, Zhang X, He J, et al. High internal quantum efficiency of nonpolar a-plane AlGaN-based multiple quantum wells grown on r-plane sapphire substrate. ACS Photonics, 2018, 5, 1903 doi: 10.1021/acsphotonics.8b00283[287] Tangi M, Mishra P, Janjua B, et al. Role of quantumconfined stark effect on bias dependent photoluminescence of N-polar GaN/InGaN multi-quantum disk amber light emitting diodes. J Appl Phys, 2018, 123, 105702 doi: 10.1063/1.5021290[288] Moustakas T D, Paiella R. Optoelectronic device physics and technology of nitride semiconductors from the UV to the terahertz. Rep Prog Phys, 2017, 80, 106501 doi: 10.1088/1361-6633/aa7bb2[289] Bartoš I, Romanyuk O, Paskova T, et al. Electron band bending and surface sensitivity: X-ray photoelectron spectroscopy of polar GaN surfaces. Surf Sci, 2017, 664, 241 doi: 10.1016/j.susc.2017.07.003[290] Jang H W, Lee J H, Lee J L. Characterization of band bendings on Ga-face and N-face GaN films grown by metalorganic chemical-vapor deposition. Appl Phys Lett, 2002, 80, 3955 doi: 10.1063/1.1481782[291] Bhat I. Physical properties of gallium nitride and related III–V nitrides. In: Wide Bandgap Semiconductor Power Devices. Woodhead Publishing, 2019, 43[292] Yonenaga I, Ohkubo Y, Deura M, et al. Elastic properties of indium nitrides grown on sapphire substrates determined by nano-indentation: In comparison with other nitrides. AIP Adv, 2015, 5, 077131 doi: 10.1063/1.4926966[293] Yim W M, Paff R J. Thermal expansion of AlN, sapphire, and silicon. J Appl Phys, 1974, 45, 1456 doi: 10.1063/1.1663432[294] Maruska H P, Tietjen J J. The preparation and properties of vapor-deposited single-crystal-line GaN. Appl Phys Lett, 1969, 15, 327 doi: 10.1063/1.1652845[295] Wright A. Elastic properties of zinc-blende and wurtzite AlN, GaN, and InN. J Appl Phys, 1997, 82, 2833 doi: 10.1063/1.366114[296] Kim K, Lambrecht W R L, Segall B. Elastic constants and related properties of tetrahedrally bonded BN, AlN, GaN, and InN. Phys Rev B, 1996, 53, 16310 doi: 10.1103/PhysRevB.53.16310[297] Polian A, Grimsditch M, Grzegory I. Elastic constants of gallium nitride. J Appl Phys, 1996, 79, 3343 doi: 10.1063/1.361236[298] Thokala R, Chaudhuri J. Calculated elastic constants of wide band gap semiconductor thin films with a hexagonal crystal structure for stress problems. Thin Solid Films, 1995, 266, 189 doi: 10.1016/0040-6090(96)80022-8[299] McNeil L E, Grimsditch M, French R H. Vibrational spectroscopy of aluminum nitride. J Am Ceram Soc, 1993, 76, 1132 doi: 10.1111/jace.1993.76.issue-5[300] Chetverikova I F, Chukichev M V, Rastorguev L N. X-ray phase analysis and elastic properties of gallium nitride. Inorg Mater, 1986, 22, 53 doi: 10.1088/0034-4885/72/3/036502[301] Rounds R, Sarkar B, Sochacki T, et al. Thermal conductivity of GaN single crystals: Influence of impurities incorporated in different growth processes. J Appl Phys, 2018, 124, 105106 doi: 10.1063/1.5047531[302] Ziade E, Yang J, Brummer G, et al. Thickness dependent thermal conductivity of gallium nitride. Appl Phys Lett, 2017, 110, 031903 doi: 10.1063/1.4974321[303] Mion C, Muth J F, Preble E A, et al. Accurate dependence of gallium nitride thermal conductivity on dislocation density. Appl Phys Lett, 2006, 89, 092123 doi: 10.1063/1.2335972[304] Harafuji K, Tsuchiya T, Kawamura K. Molecular dynamics simulation for evaluating melting point of wurtzite-type GaN crystal. J Appl Phys, 2004, 96, 2501 doi: 10.1063/1.1772878[305] Levinshtein M E, Rumyantsev S L, Shur M S. Properties of Advanced Semiconductor Materials: GaN, AIN, InN, BN, SiC, SiGe. John Wiley & Sons, 2001[306] Morkoc H, Strite S, Gao G, et al. Large-band-gap SiC, III-V nitride, and II-VI ZnSe-based semiconductor device technologies. J Appl Phys, 1994, 76, 1363 doi: 10.1063/1.358463[307] Berger L I. Semiconductor materials. CRC Press, 1997, 123[308] Grzegory I, Krukowski S, Jun J, et al. Stability of indium nitride at N2 pressure up to 20 kbar. AIP Conf Proc, 1994, 309, 565 doi: 10.1063/1.46099[309] Slack G A, Tanzilli R A, Pohl R O, et al. The intrinsic thermal conductivity of AIN. J Phys Chem Solids, 1987, 48, 641 doi: 10.1016/0022-3697(87)90153-3[310] Barin I, Knacke O, Kubaschewski O. Thermochemical properties of inorganic substances. Springer-Verlag, 1977[311] Slack G A, McNelly T F. AlN single crystals. J Cryst Growth, 1977, 42, 560 doi: 10.1016/0022-0248(77)90246-9[312] Slack G A, McNelly T F. Growth of high purity AlN crystals. J Cryst Growth, 1976, 34, 263 doi: 10.1016/0022-0248(76)90139-1[313] Slack G A, Bartram S F. Thermal expansion of some diamondlike crystals. J Appl Phys, 1975, 46, 89 doi: 10.1063/1.321373[314] Mezaki R, Tilleux E W, Jambois T F,et al. Specific heat of nonmetallic solids. Plenum Press, 1970[315] Tyagai V A, Evstigneev A M, Krasiko A N, et al. Optical properties of indium nitride films. Sov Phys Semicond, 1977, 11, 1257[316] Barker A S Jr, Ilegems M. Infrared lattice vibrations and free-electron dispersion in GaN. Phys Rev B, 1973, 7, 743 doi: 10.1103/PhysRevB.7.743[317] Wagner J M, Bechstedt F. Properties of strained wurtzite GaN and AlN: Ab initio studies. Phys Rev B, 2002, 66, 115202 doi: 10.1103/PhysRevB.66.115202[318] Krukowski S, Witek A, Adamczyk J, et al. Thermal properties of indium nitride. J Phys Chem Solids, 1998, 59, 289 doi: 10.1016/S0022-3697(97)00222-9[319] Doppalapudi D, Moustakas T D. Epitaxial growth and structure of III–V nitride thin films. In: Handbook of Thin Films. Elsevier, 2002, 57[320] You S T, Lo I, Shih H J, et al. Strain of m-plane GaN epitaxial layer grown on β-LiGaO2(100) by plasma-assisted molecular beam epitaxy. AIP Adv, 2018, 8, 075116 doi: 10.1063/1.5037006[321] Davies M J, Dawson P, Massabuau F C P, et al. The effects of varying threading dislocation density on the optical properties of InGaN/GaN quantum wells. Phys Status Solidi C, 2014, 11, 750 doi: 10.1002/pssc.v11.3/4[322] Zhang J P, Wang H M, Gaevski M E, et al. Crack-free thick AlGaN grown on sapphire using AlN/AlGaN superlattices for strain management. Appl Phys Lett, 2002, 80, 3542 doi: 10.1063/1.1477620[323] Dong P, Yan J, Wang J, et al. 282-nm AlGaN-based deep ultraviolet light-emitting diodes with improved performance on nano-patterned sapphire substrates. Appl Phys Lett, 2013, 102, 241113 doi: 10.1063/1.4812237[324] Bryan Z, Bryan I, Xie J, et al. High internal quantum efficiency in AlGaN multiple quantum wells grown on bulk AlN substrates. Appl Phys Lett, 2015, 106, 142107 doi: 10.1063/1.4917540[325] Grandusky J R, Smart J A, Mendrick M C, et al. Pseudomorphic growth of thick n-type Al xGa1– xN layers on low-defect-density bulk AlN substrates for UV LED applications. J Cryst Growth, 2009, 311, 2864 doi: 10.1016/j.jcrysgro.2009.01.101[326] Graham D M, Soltani-Vala A, Dawson P, et al. Optical and microstructural studies of InGaN/GaN single-quantum-well structures. J Appl Phys, 2005, 97, 103508 doi: 10.1063/1.1897070[327] Nakamura S, Senoh M, Mukai T. High-power InGaN/GaN double-heterostructure violet light emitting diodes. Appl Phys Lett, 1993, 62, 2390 doi: 10.1063/1.109374[328] Usami S, Ando Y, Tanaka A, et al. Correlation between dislocations and leakage current of p–n diodes on a free-standing GaN substrate. Appl Phys Lett, 2018, 112, 182106 doi: 10.1063/1.5024704[329] Ferdous M S, Wang X, Fairchild M N, et al. Effect of threading defects on InGaN/GaN multiple quantum well light emitting diodes. Appl Phys Lett, 2007, 91, 231107 doi: 10.1063/1.2822395[330] Kamiyama S, Iwaya M, Takanami S, et al. UV light-emitting diode fabricated on hetero-ELO-grown Al0.22Ga0.78N with low dislocation density. Phys Status Solidi A, 2002, 192, 296 doi: 10.1002/1521-396X(200208)192:2<296::AID-PSSA296>3.0.CO;2-Z[331] Nakamura S. The roles of structural imperfections in InGaNbased blue light-emitting diodes and laser diodes. Science, 1998, 281, 956 doi: 10.1126/science.281.5379.956[332] Massabuau F C, Rhode S L, Horton M K, et al. Dislocations in AlGaN: Core structure, atom segregation, and optical properties. Nano Lett, 2017, 17, 4846 doi: 10.1021/acs.nanolett.7b01697[333] Holec D, Costa P M F J, Kappers M J, et al. Critical thickness calculations for InGaN/GaN. J Cryst Growth, 2007, 303, 314 doi: 10.1016/j.jcrysgro.2006.12.054[334] Holec D, Zhang Y, Rao D V S, et al. Equilibrium critical thickness for misfit dislocations in III-nitrides. J Appl Phys, 2008, 104, 123514 doi: 10.1063/1.3033553[335] Yang X, Nitta S, Nagamatsu K, et al. Growth of hexagonal boron nitride on sapphire substrate by pulsed-mode metalorganic vapor phase epitaxy. J Cryst Growth, 2018, 482, 1 doi: 10.1016/j.jcrysgro.2017.10.036[336] Creighton J R, Coltrin M E, Figiel J J. Measurement and thermal modeling of sapphire substrate temperature at III–nitride MOVPE conditions. J Cryst Growth, 2017, 464, 132 doi: 10.1016/j.jcrysgro.2016.11.063[337] Hirayama H, Fujikawa S, Noguchi N, et al. 222–282 nm AlGaN and InAlGaN-based deep-UV LEDs fabricated on high-quality AlN on sapphire. Phys Status Solidi A, 2009, 206, 1176 doi: 10.1002/pssa.v206:6[338] Weeks T W Jr, Bremser M D, Ailey K S, et al. GaN thin films deposited via organometallic vapor phase epitaxy on α(6H)-SiC(0001) using high-temperature monocrystalline AlN buffer layers. Appl Phys Lett, 1995, 67, 401 doi: 10.1063/1.114642[339] Akasaki I, Amano H, Koide Y, et al. Effects of AlN buffer layer on crystallographic structure and on electrical and optical properties of GaN and Ga1– xAl xN (0 < x ≤ 0.4) films grown on sapphire substrate by MOVPE. J Cryst Growth, 1989, 98, 209 doi: 10.1016/0022-0248(89)90200-5[340] Matta S, Brault J, Ngo T H, et al. Photoluminescence properties of (Al,Ga)N nanostructures grown on Al0.5Ga0.5N (0001). Superlattices Microstruct, 2018, 114, 161 doi: 10.1016/j.spmi.2017.12.029[341] Hirayama H, Fujikawa S, Norimatsu J, et al. Fabrication of a low threading dislocation density ELO-AlN template for application to deep-UV LEDs. Phys Status Solidi C, 2009, 6, S356 doi: 10.1002/pssc.200880958[342] Xu Q, Liu B, Zhang S, et al. Structural and optical properties of AlxGa1–xN (0.33 ≤ x ≤ 0.79) layers on high-temperature AlN interlayer grown by metal organic chemical vapor deposition. Superlattices Microstruct, 2017, 101, 144 doi: 10.1016/j.spmi.2016.11.029[343] Khan M A, Shatalov M, Maruska H P, et al. III-nitride UV devices. Jpn J Appl Phys, 2005, 44, 7191 doi: 10.1143/JJAP.44.7191[344] Keller S, DenBaars S P. Metalorganic chemical vapor deposition of group III nitrides — a discussion of critical issues. J Cryst Growth, 2003, 248, 479 doi: 10.1016/S0022-0248(02)01867-5[345] Wu X H, Fini P, Tarsa E J, et al. Dislocation generation in GaN heteroepitaxy. J Cryst Growth, 1998, 189, 231 doi: 10.1016/S0022-0248(98)00240-1[346] Imura M, Nakano K, Fujimoto N, et al. Dislocations in AlN epilayers grown on sapphire substrate by high-temperature metal-organic vapor phase epitaxy. Jpn J Appl Phys, 2007, 46, 1458 doi: 10.1143/JJAP.46.1458[347] Narayanan V, Lorenz K, Kim W, et al. Origins of threading dislocations in GaN epitaxial layers grown on sapphire by metalorganic chemical vapor deposition. Appl Phys Lett, 2001, 78, 1544 doi: 10.1063/1.1352699[348] Wang H M, Zhang J P, Chen C Q, et al. AlN/AlGaN superlattices as dislocation filter for low-threading-dislocation thick AlGaN layers on sapphire. Appl Phys Lett, 2002, 81, 604 doi: 10.1063/1.1494858[349] Jiang H, Egawa T, Hao M, et al. Reduction of threading dislocations in AlGaN layers grown on AlN/sapphire templates using high-temperature GaN interlayer. Appl Phys Lett, 2005, 87, 241911 doi: 10.1063/1.2143126[350] Tersoff J. Dislocations and strain relief in compositionally graded layers. Appl Phys Lett, 1993, 62, 693 doi: 10.1063/1.108842[351] Ivanov S V, Nechaev D V, Sitnikova A A, et al. Plasma-assisted molecular beam epitaxy of Al(Ga)N layers and quantum well structures for optically pumped mid-UV lasers on c-Al2O3. Semicond Sci Technol, 2014, 29, 084008 doi: 10.1088/0268-1242/29/8/084008[352] Cho J, Schubert E F, Kim J K. Efficiency droop in light-emitting diodes: Challenges and countermeasures. Laser Photonics Rev, 2013, 7, 408 doi: 10.1002/lpor.201200025[353] Janjua B, Sun H, Zhao C, et al. Droop-free AlxGa1– xN/AlyGa1– yN quantum-disks-in-nanowires ultraviolet LED emitting at 337 nm on metal/silicon substrates. Opt Express, 2017, 25, 1381 doi: 10.1364/OE.25.001381[354] Kim T, Seong T Y, Kwon O. Investigating the origin of efficiency droop by profiling the voltage across the multi-quantum well of an operating light-emitting diode. Appl Phys Lett, 2016, 108, 231101 doi: 10.1063/1.4953401[355] Jung E, Hwang G, Chung J, et al. Investigating the origin of efficiency droop by profiling the temperature across the multi-quantum well of an operating light-emitting diode. Appl Phys Lett, 2015, 106, 041114 doi: 10.1063/1.4907177[356] Verzellesi G, Saguatti D, Meneghini M, et al. Efficiency droop in InGaN/GaN blue light-emitting diodes: Physical mechanisms and remedies. J Appl Phys, 2013, 114, 071101 doi: 10.1063/1.4816434[357] Kim M H, Schubert M F, Dai Q, et al. Origin of efficiency droop in GaN-based light-emitting diodes. Appl Phys Lett, 2007, 91, 183507 doi: 10.1063/1.2800290[358] Efremov A A, Bochkareva N, Gorbunov R I, et al. Effect of the joule heating on the quantum efficiency and choice of thermal conditions for high-power blue InGaN/GaN LEDs. Semiconductors, 2006, 40, 605 doi: 10.1134/S1063782606050162[359] Yang Y, Cao X A, Yan C. Investigation of the nonthermal mechanism of efficiency rolloff in InGaN light-emitting diodes. IEEE Trans Electron Devices, 2008, 55, 1771 doi: 10.1109/TED.2008.923561[360] Mukai T, Yamada M, Nakamura S. Characteristics of InGaN-based UV/blue/green/amber/red light-emitting diodes. Jpn J Appl Phys, 1999, 38, 3976 doi: 10.1143/JJAP.38.3976[361] Meng X, Wang L, Hao Z, et al. Study on efficiency droop in InGaN/GaN light-emitting diodes based on differential carrier lifetime analysis. Appl Phys Lett, 2016, 108, 013501 doi: 10.1063/1.4939593[362] Schubert M F, Xu J, Kim J K, et al. Polarization-matched GaInN/AlGaInN multi-quantum-well light-emitting diodes with reduced efficiency droop. Appl Phys Lett, 2008, 93, 041102 doi: 10.1063/1.2963029[363] Meyaard D S, Lin G B, Cho J, et al. Identifying the cause of the efficiency droop in GaInN light-emitting diodes by correlating the onset of high injection with the onset of the efficiency droop. Appl Phys Lett, 2013, 102, 251114 doi: 10.1063/1.4811558[364] Bochkareva N I, Rebane Y T, Shreter Y G. Efficiency droop in GaN LEDs at high current densities: Tunneling leakage currents and incomplete lateral carrier localization in InGaN/GaN quantum wells. Semiconductors, 2014, 48, 1079 doi: 10.1134/S1063782614080065[365] Rozhansky I V, Zakheim D A. Analysis of the causes of the decrease in the electroluminescence efficiency of AlGaInN light-emitting-diode heterostructures at high pumping density. Semiconductors, 2006, 40, 839 doi: 10.1134/S1063782606070190[366] Piprek J. Efficiency droop in nitride-based light-emitting diodes. Phys Status Solidi A, 2010, 207, 2217 doi: 10.1002/pssa.v207:10[367] Hai X, Rashid R T, Sadaf S M, et al. Effect of low hole mobility on the efficiency droop of AlGaN nanowire deep ultraviolet light emitting diodes. Appl Phys Lett, 2019, 114, 101104 doi: 10.1063/1.5091517[368] Frost T, Jahangir S, Stark E, et al. Monolithic electrically injected nanowire array edge-emitting laser on (001) silicon. Nano Lett, 2014, 14, 4535 doi: 10.1021/nl5015603[369] Iveland J, Martinelli L, Peretti J, et al. Direct measurement of Auger electrons emitted from a semiconductor light-emitting diode under electrical injection: Identification of the dominant mechanism for efficiency droop. Phys Rev Lett, 2013, 110, 177406 doi: 10.1103/PhysRevLett.110.177406[370] Wang L, Jin J, Mi C, et al. A review on experimental measurements for understanding efficiency droop in InGaN-based light-emitting diodes. Materials, 2017, 10, 1233 doi: 10.3390/ma10111233[371] Yoshida H, Kuwabara M, Yamashita Y, et al. Radiative and nonradiative recombination in an ultraviolet GaN/AlGaN multiple-quantum-well laser diode. Appl Phys Lett, 2010, 96, 211122 doi: 10.1063/1.3442918[372] Morkoç H. Handbook of nitride semiconductors and devices, materials properties, physics and growth. Vol. 3. John Wiley & Sons, 2009[373] Hader J, Moloney J V, Pasenow B, et al. On the importance of radiative and Auger losses in GaN-based quantum wells. Appl Phys Lett, 2008, 92, 261103 doi: 10.1063/1.2953543[374] Delaney K T, Rinke P, Van de Walle C G. Auger recombination rates in nitrides from first principles. Appl Phys Lett, 2009, 94, 191109 doi: 10.1063/1.3133359[375] Delaney K T, Rinke P, Van de Walle C G. Erratum: " Auger recombination rates in nitrides from first principles” [Appl. Phys. Lett. 94, 191109(2009)]. Appl Phys Lett, 2016, 108, 259901 doi: 10.1063/1.4954177[376] Guo W, Zhang M, Bhattacharya P, et al. Auger recombination in III-nitride nanowires and its effect on nanowire light-emitting diode characteristics. Nano Lett, 2011, 11, 1434 doi: 10.1021/nl103649d[377] Liu L, Wang L, Liu N, et al. Investigation of the light emission properties and carrier dynamics in dual-wavelength InGaN/GaN multiple-quantum well light emitting diodes. J Appl Phys, 2012, 112, 083101 doi: 10.1063/1.4759373[378] Berdahl P. Radiant refrigeration by semiconductor diodes. J Appl Phys, 1985, 58, 1369 doi: 10.1063/1.336309[379] David A, Hurni C A, Young N G, et al. Electrical properties of III-Nitride LEDs: Recombination-based injection model and theoretical limits to electrical efficiency and electroluminescent cooling. Appl Phys Lett, 2016, 109, 083501 doi: 10.1063/1.4961491[380] Kibria M G, Qiao R, Yang W, et al. Atomic-scale origin of long-term stability and high performance of p-GaN nanowire arrays for photocatalytic overall pure water splitting. Adv Mater, 2016, 28, 8388 doi: 10.1002/adma.201602274[381] Yong Y, Jiang H, Li X, et al. The cluster-assembled nanowires based on M12N12(M = Al and Ga) clusters as potential gas sensors for CO, NO, and NO2 detection. Phys Chem Chem Phys, 2016, 18, 21431 doi: 10.1039/C6CP02931K[382] Alfaraj N, Muhammed M M, Li K H, et al. Thermodynamic photoinduced disorder in AlGaN nanowires. AIP Adv, 2017, 7, 125113 doi: 10.1063/1.5003443[383] Alfaraj N, Mitra S, Wu F, et al. Photoinduced entropy of InGaN/GaN p–i–n double-heterostructure nanowires. Appl Phys Lett, 2017, 110, 161110 doi: 10.1063/1.4981252[384] Wang J B, Johnson S, Ding D, et al. Influence of photon recycling on semiconductor luminescence refrigeration. J Appl Phys, 2006, 100, 043502 doi: 10.1063/1.2219323[385] Dawson P, Schulz S, Oliver R A, et al. The nature of carrier localisation in polar and nonpolar InGaN/GaN quantum wells. J Appl Phys, 2016, 119, 181505 doi: 10.1063/1.4948237[386] Badcock T J, Dawson P, Davies M J, et al. Low temperature carrier redistribution dynamics in InGaN/GaN quantum wells. J Appl Phys, 2014, 115, 113505 doi: 10.1063/1.4868628[387] Li C K, Piccardo M, Lu L S, et al. Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes. Phys Rev B, 2017, 95, 144206 doi: 10.1103/PhysRevB.95.144206[388] Belloeil M, Gayral B, Daudin B. Quantum dot-like behavior of compositional fluctuations in AlGaN nanowires. Nano Lett, 2016, 16, 960 doi: 10.1021/acs.nanolett.5b03904[389] Zhao S, Woo S Y, Bugnet M, Liu X., et al Three-dimensional quantum confinement of charge carriers in self-organized AlGaN nanowires: A viable route to electrically injected deep ultraviolet lasers. Nano Lett, 2015, 15, 7801 doi: 10.1021/acs.nanolett.5b02133[390] Mahajan S. Phase separation and atomic ordering in mixed III nitride layers. Scr Mater, 2014, 75, 1 doi: 10.1016/j.scriptamat.2013.11.018[391] Li D, Jiang K, Sun X, et al. AlGaN photonics: recent advances in materials and ultraviolet devices. Adv Opt Photonics, 2018, 10, 43 doi: 10.1364/AOP.10.000043[392] He J, Wang S, Chen J, et al. Localized surface plasmon enhanced deep UV-emitting of AlGaN based multi-quantum wells by Al nanoparticles on SiO2 dielectric interlayer. Nanotechnology, 2018, 29, 195203 doi: 10.1088/1361-6528/aab168[393] Yoshikawa A, Nagatomi T, Morishita T, et al. High-quality AlN film grown on a nanosized concave-convex surface sapphire substrate by metalorganic vapor phase epitaxy. Appl Phys Lett, 2017, 111, 162102 doi: 10.1063/1.5008258[394] Jiang K, Sun X, Ben J, et al. The defect evolution in homoepitaxial AlN layers grown by high-temperature metal-organic chemical vapor deposition. Cryst Eng Comm, 2018, 20, 2720 doi: 10.1039/C8CE00287H[395] Miyoshi M, Ohta M, Mori T, et al. A comparative study of InGaN/GaN multiple-quantum-well solar sells grown on sapphire and AlN template by metalorganic chemical vapor deposition. Phys Status Solidi A, 2018, 215, 1700323 doi: 10.1002/pssa.201700323[396] Yoshida S, Misawa S, Gonda S. Improvements on the electrical and luminescent properties of reactive molecular beam epitaxially grown GaN films by using AlN-coated sapphire substrates. Appl Phys Lett, 1983, 42, 427 doi: 10.1063/1.93952[397] Amano H, Sawaki N, Akasaki I, et al. Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer. Appl Phys Lett, 1986, 48, 353 doi: 10.1063/1.96549[398] Nakamura S, Senoh M, Mukai T. P-GaN/N-InGaN/NGaN double-heterostructure blue-light-emitting diodes. Jpn J Appl Phys, 1993, 32, L8 doi: 10.1143/JJAP.32.L8[399] Asif Khan M, Kuznia J N, Olson D T, et al. Microwave performance of a 0.25 μm gate AlGaN/GaN heterostructure field effect transistor. Appl Phys Lett, 1994, 65, 1121 doi: 10.1063/1.112116[400] Zhao S, Woo S Y, Sadaf S M, et al. Molecular beam epitaxy growth of Al-rich AlGaN nanowires for deep ultraviolet optoelectronics. APL Mater, 2016, 4, 086115 doi: 10.1063/1.4961680[401] Himwas C, Den Hertog M, Dang L S, et al. Alloy inhomogeneity and carrier localization in AlGaN sections and AlGaN/AlN nanodisks in nanowires with 240–350 nm emission. Appl Phys Lett, 2014, 105, 241908 doi: 10.1063/1.4904989[402] Khan A, Balakrishnan K, Katona T. Ultraviolet light-emitting diodes based on group three nitrides. Nat Photonics, 2008, 2, 77 doi: 10.1038/nphoton.2007.293[403] Ristić J, Sánchez-García M, Calleja E, et al. AlGaN nanocolumns grown by molecular beam epitaxy: Optical and structural characterization. Phys Status Solidi A, 2002, 192, 60 doi: 10.1002/1521-396x(200207)192:1<60::aid-pssa60>3.0.co;2-o[404] Vuong T Q P, Cassabois G, Valvin P, et al. Deep ultraviolet emission in hexagonal boron nitride grown by high-temperature molecular beam epitaxy. 2D Mater, 2017, 4, 021023 doi: 10.1088/2053-1583/aa604a[405] Liu X, Zhao S, Le B H, et al. Molecular beam epitaxial growth and characterization of AlN nanowall deep UV light emitting diodes. Appl Phys Lett, 2017, 111, 101103 doi: 10.1063/1.4989551[406] SaifAddin B K, Almogbel A, Zollner C, et al. Fabrication technology for high light-extraction ultraviolet thin-film flip-chip (UV TFFC) LEDs grown on SiC. Semicond Sci Technol, 2019, 43, 035007 doi: 10.1088/1361-6641/aaf58f[407] Alias M S, Janjua B, Zhao C, et al. Enhancing the light-extraction efficiency of AlGaN nanowires ultraviolet light-emitting diode by using nitride/air distributed Bragg reflector nanogratings. IEEE Photonics J, 2017, 9, 4900508 doi: 10.1109/JPHOT.2017.2749198[408] Park J S, Kim J K, Cho J, et al. Review- Group III-nitride-based ultraviolet light-emitting diodes: Ways of increasing external quantum efficiency. ECS J Solid State Sci Technol, 2017, 6, Q42 doi: 10.1149/2.0111704jss[409] Kneissl M, Rass J. III-nitride ultraviolet emitters. In: Springer Series in Materials Science. Vol. 227. Springer, 2016[410] Yamada K, Furusawa Y, Nagai S, et al. Development of underfilling and encapsulation for deep-ultraviolet LEDs. Appl Phys Express, 2015, 8, 012101 doi: 10.7567/APEX.8.012101[411] Maeda N, Hirayama H. Realization of high-efficiency deep-UV LEDs using transparent p-AlGaN contact layer. Phys Status Solidi C, 2013, 10, 1521 doi: 10.1002/pssc.201300278[412] Kim B J, Jung H, Shin J, et al. Enhancement of light extraction efficiency of ultraviolet light emitting diodes by patterning of SiO2 nanosphere arrays. Thin Solid Films, 2009, 517, 2742 doi: 10.1016/j.tsf.2008.11.067[413] Jo M, Maeda N, Hirayama H. Enhanced light extraction in 260 nm light-emitting diode with a highly transparent pAlGaN layer. Appl Phys Express, 2016, 9, 012102 doi: 10.7567/APEX.9.012102[414] Kinoshita T, Obata T, Yanagi H, et al. High p-type conduction in high-Al content Mg-doped AlGaN. Appl Phys Lett, 2013, 102, 012105 doi: 10.1063/1.4773594[415] Kozodoy P, Xing H, DenBaars S P, et al. Heavy doping effects in Mg-doped GaN. J Appl Phys, 2000, 87, 1832 doi: 10.1063/1.372098[416] Chen Y, Wu H, Han E, et al. High hole concentration in p-type AlGaN by indium-surfactant-assisted Mg-delta doping. Appl Phys Lett, 2015, 106, 162102 doi: 10.1063/1.4919005[417] Aoyagi Y, Takeuchi M, Iwai S, et al. High hole carrier concentration realized by alternative co-doping technique in metal organic chemical vapor deposition. Appl Phys Lett, 2011, 99, 112110 doi: 10.1063/1.3641476[418] Kauser M Z, Osinsky A, Dabiran A M, et al. Enhanced vertical transport in p-type AlGaN/GaN superlattices. Appl Phys Lett, 2004, 85, 5275 doi: 10.1063/1.1828230[419] Luo W, Liu B, Li Z, et al. Enhanced p-type conduction in AlGaN grown by metal-source flow-rate modulation epitaxy. Appl Phys Lett, 2018, 113, 072107 doi: 10.1063/1.5040334[420] Detchprohm T, Liu Y S, Mehta K, et al. Sub 250 nm deep-UV AlGaN/AlN distributed Bragg reflectors. Appl Phys Lett, 2017, 110, 011105 doi: 10.1063/1.4973581[421] Alias M S, Alatawi A A, Chong W K, et al. High reflectivity YDH/SiO2 distributed Bragg reflector for UV-C wavelength regime. IEEE Photonics J, 2018, 10, 2200508 doi: 10.1109/jphot.2018.2804355[422] Majety S, Li J, Cao X K, et al. Epitaxial growth and demonstration of hexagonal BN/AlGaN p–n junctions for deep ultraviolet photonics. Appl Phys Lett, 2012, 100, 061121 doi: 10.1063/1.3682523[423] Dahal R, Li J, Majety S, et al. Epitaxially grown semiconducting hexagonal boron nitride as a deep ultraviolet photonic material. Appl Phys Lett, 2011, 98, 211110 doi: 10.1063/1.3593958[424] He B, Zhang W J, Yao Z Q, et al. p-type conduction in beryllium-implanted hexagonal boron nitride films. Appl Phys Lett, 2009, 95, 252106 doi: 10.1063/1.3276065[425] Nose K, Oba H, Yoshida T. Electric conductivity of boron nitride thin films enhanced by in situ doping of zinc. Appl Phys Lett, 2006, 89, 112124 doi: 10.1063/1.2354009[426] Lu M, Bousetta A, Bensaoula A, et al. Electrical properties of boron nitride thin films grown by neutralized nitrogen ion assisted vapor deposition. Appl Phys Lett, 1996, 68, 622 doi: 10.1063/1.116488[427] Nakarmi M L, Kim K H, Khizar M, et al. Electrical and optical properties of Mg-doped Al0.7Ga0.3N alloys. Appl Phys Lett, 2005, 86, 092108 doi: 10.1063/1.1879098[428] Yan Q, Janotti A, Scheffler M, et al. Origins of optical absorption and emission lines in AlN. Appl Phys Lett, 2014, 105, 111104 doi: 10.1063/1.4895786[429] Takeuchi M, Ooishi S, Ohtsuka T, et al. Improvement of Al-polar AlN layer quality by three-stage flow-modulation metalorganic chemical vapor deposition. Appl Phys Express, 2008, 1, 021102 doi: 10.1143/APEX.1.021102[430] Takeuchi M, Shimizu H, Kajitani R, et al. Al- and N-polar AlN layers grown on c-plane sapphire substrates by modified flow-modulation MOCVD. J Cryst Growth, 2007, 305, 360 doi: 10.1016/j.jcrysgro.2007.04.004[431] Kikkawa J, Nakamura Y, Fujinoki N, et al. Investigating the origin of intense photoluminescence in Si capping layer on Ge1– xSnx nanodots by transmission electron microscopy. J Appl Phys, 2013, 113, 074302 doi: 10.1063/1.4792647[432] Huang C Y, Wu P Y, Chang K S, et al. High-quality and highly-transparent AlN template on annealed sputter-deposited AlN buffer layer for deep ultraviolet light-emitting diodes. AIP Adv, 2017, 7, 055110 doi: 10.1063/1.4983708[433] Miyake H, Nishio G, Suzuki S, et al. Annealing of an AlN buffer layer in N2–CO for growth of a high-quality AlN film on sapphire. Appl Phys Express, 2016, 9, 025501 doi: 10.7567/APEX.9.025501[434] Miyake H, Lin C H, Tokoro K, et al. Preparation of high-quality AlN on sapphire by high-temperature face-to-face annealing. J Cryst Growth, 2016, 456, 155 doi: 10.1016/j.jcrysgro.2016.08.028[435] Iriarte G F. Influence of the magnetron on the growth of aluminum nitride thin films deposited by reactive sputtering. J Vac Sci Technol, 2010, 28, 193 doi: 10.1116/1.3280174[436] Ide K, Matsubara Y, Iwaya M, et al. Microstructure analysis of AlGaN on AlN underlying layers with different threading dislocation densities. Jpn J Appl Phys, 2013, 52, 08JE22 doi: 10.7567/JJAP.52.08JE22[437] Nonaka K, Asai T, Ban K, et al. Microstructural analysis of thick AlGaN epilayers using Mg-doped AlN underlying layer. Phys Status Solidi C, 2011, 8, 1467 doi: 10.1002/pssc.201001114[438] Asai T, Nonaka K, Ban K, et al. Growth of low-dislocation-density AlGaN using Mg-doped AlN underlying layer. Phys Status Solidi C, 2010, 7, 2101 doi: 10.1002/pssc.200983591[439] Sun H, Wu F, Al Tahtamouni T M, et al. Structural properties, crystal quality and growth modes of MOCVD-grown AlN with TMAl pretreatment of sapphire substrate. J Phys D, 2017, 50, 395101 doi: 10.1088/1361-6463/aa8503[440] Hussey L, White R M, Kirste R, et al. Sapphire decomposition and inversion domains in N-polar aluminum nitride. Appl Phys Lett, 2014, 104, 032104 doi: 10.1063/1.4862982[441] Wong M H, Wu F, Speck J S, et al. Polarity inversion of N-face GaN using an aluminum oxide interlayer. J Appl Phys, 2010, 108, 123710 doi: 10.1063/1.3524473[442] Lim D H, Xu K, Arima S, et al. Polarity inversion of GaN films by trimethyl-aluminum preflow in low-pressure metalorganic vapor phase epitaxy growth. J Appl Phys, 2002, 91, 6461 doi: 10.1063/1.1471384[443] Eom D, Kim J, Lee K, et al. Fabrication of AlN nano-structures using polarity control by high temperature metalorganic chemical vapor deposition. J Nanosci Nanotechnol, 2015, 15, 5144 doi: 10.1166/jnn.2015.10368[444] Liu X, Sun C, Xiong B, et al. Aluminum nitride-on-sapphire platform for integrated high-Q microresonators. Opt Express, 2017, 25, 587 doi: 10.1364/OE.25.000587[445] Lee D, Lee J W, Jang J, et al. Improved performance of AlGaN-based deep ultraviolet light-emitting diodes with nanopatterned AlN/sapphire substrates. Appl Phys Lett, 2017, 110, 191103 doi: 10.1063/1.4983283[446] Zhou S, Hu H, Liu X, et al. Comparative study of GaN-based ultraviolet LEDs grown on different-sized patterned sapphire substrates with sputtered AlN nucleation layer. Jpn J Appl Phys, 2017, 56, 111001 doi: 10.7567/JJAP.56.111001[447] Wang S, Dai J, Hu J, et al. Ultrahigh degree of optical polarization above 80% in AlGaN-based deep-ultraviolet LED with moth-eye microstructure. ACS Photonics, 2018, 5, 3534 doi: 10.1021/acsphotonics.8b00899[448] Shen X Q, Takahashi T, Ide T, et al. High quality thin AlN epilayers grown on Si(110) substrates by metalorganic chemical vapor deposition. CrystEngComm, 2017, 19, 1204 doi: 10.1039/C6CE02542K[449] Tran B T, Maeda N, Jo M, et al. Performance improvement of AlN crystal quality grown on patterned Si(111) substrate for deep UV-LED applications. Sci Rep, 2016, 6, 35681 doi: 10.1038/srep35681[450] Ooi Y K, Zhang J. Light extraction efficiency analysis of flip-chip ultraviolet light-emitting diodes with patterned sapphire substrate. IEEE Photonics J, 2018, 10, 8200913 doi: 10.1109/JPHOT.2018.2847226[451] Bhattacharyya A, Moustakas T D, Zhou L, et al. Deep ultraviolet emitting AlGaN quantum wells with high internal quantum efficiency. Appl Phys Lett, 2009, 94, 181907 doi: 10.1063/1.3130755[452] Susilo N, Enslin J, Sulmoni L, et al. Effect of the GaN:Mg contact layer on the light-output and current-voltage characteristic of UVB LEDs. Phys Status Solidi A, 2018, 215, 1700643 doi: 10.1002/pssa.201700643[453] Akaike R, Ichikawa S, Funato M, et al. Al xGa1– xN-based semipolar deep ultraviolet light-emitting diodes. Appl Phys Express, 2018, 11, 061001 doi: 10.7567/APEX.11.061001[454] Liu X, Mashooq K, Szkopek T, et al. Improving the efficiency of transverse magnetic polarized emission from AlGaN based LEDs by using nanowire photonic crystal. IEEE Photonics J, 2018, 10, 4501211 doi: 10.1109/JPHOT.2018.2842110[455] Liu D, Cho S J, Park J, et al. 229 nm UV LEDs on aluminum nitride single crystal substrates using p-type silicon for increased hole injection. Appl Phys Lett, 2018, 112, 081101 doi: 10.1063/1.5011180[456] Liu C, Ooi Y K, Islam S M, et al. 234 nm and 246 nm AlN-delta-GaN quantum well deep ultraviolet light-emitting diodes. Appl Phys Lett, 2018, 112, 011101 doi: 10.1063/1.5007835[457] Inoue S i, Tamari N, Taniguchi M. 150 mW deep-ultraviolet light-emitting diodes with large-area AlN nanophotonic light-extraction structure emitting at 265 nm. Appl Phys Lett, 2017, 110, 141106 doi: 10.1063/1.4978855[458] Sarwar A T M G, May B J, et al. Effect of quantum well shape and width on deep ultraviolet emission in AlGaN nanowire LEDs. Phys Status Solidi A, 2016, 213, 947 doi: 10.1002/pssa.201532735[459] Kent T F, Carnevale S D, Sarwar A, et al. Deep ultraviolet emitting polarization induced nanowire light emitting diodes with Al xGa1– xN active regions. Nanotechnology, 2014, 25, 455201 doi: 10.1088/0957-4484/25/45/455201[460] Moustakas T D, Liao Y, Kao C K, et al. Deep UV-LEDs with high IQE based on AlGaN alloys with strong band structure potential fluctuations. In: Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVI. Vol. 8278. 2012, 82780L[461] Liao Y, Thomidis C, Kao C K. et al AlGaN based deep ultraviolet light emitting diodes with high internal quantum efficiency grown by molecular beam epitaxy. Appl Phys Lett, 2011, 98, 081110 doi: 10.1063/1.3559842[462] Cabalu J S, Bhattacharyya A, Thomidis C, et al. High power ultraviolet light emitting diodes based on GaN/AlGaN quantum wells produced by molecular beam epitaxy. J Appl Phys, 2006, 100, 104506 doi: 10.1063/1.2388127[463] Molnar R J, Lei T, Moustakas T D. Electron transport mechanism in gallium nitride. Appl Phys Lett, 1993, 62, 72 doi: 10.1063/1.108823[464] Muñoz E, Monroy E, Calle F, et al. AlGaN photodiodes for monitoring solar UV radiation. J Geophys Res Atmos, 2000, 105, 4865 doi: 10.1029/1999JD900939[465] Monroy E, Calle F, Pau J, et al. AlGaN-based UV photodetectors. J Cryst Growth, 2001, 230, 537 doi: 10.1016/S0022-0248(01)01305-7[466] Chowdhury U, Wong M M, Collins C J, et al . High-performance solar-blind photodetector using an Al0.6Ga0.4N n-type window layer. J Cryst Growth, 2003, 248, 552 doi: 10.1016/S0022-0248(02)01877-8[467] Asgari A, Ahmadi E, Kalafi M. Al xGa1– xN/GaN multi-quantum-well ultraviolet detector based on p-i-n heterostructures. Microelectron J, 2009, 40, 104 doi: 10.1016/j.mejo.2008.06.087[468] Larason T, Ohno Y. Calibration and characterization of UV sensors for water disinfection. Metrologia, 2006, 43, S151 doi: 10.1088/0026-1394/43/2/S30[469] Oubei H M, Shen C, Kammoun A, et al. Light based underwater wireless communications. Jpn J Appl Phys, 2018, 57, 08PA06 doi: 10.7567/JJAP.57.08PA06[470] Werner M R, Fahrner W R. Review on materials, microsensors, systems and devices for high-temperature and harsh-environment applications. IEEE Trans Ind Electron, 2001, 48, 249 doi: 10.1109/41.915402[471] Neuberger R, Müller G, Ambacher O, et al. High-electron-mobility AlGaN/GaN Transistors (HEMTs) for fluid monitoring applications. Phys Status Solidi A, 2001, 185, 85 doi: 10.1002/1521-396x(200105)185:1<85::aid-pssa85>3.0.co;2-u[472] Miller R A, So H, Chiamori H C, et al. A microfabricated sun sensor using GaN-on-sapphire ultraviolet photodetector arrays. Rev Sci Instrum, 2016, 87, 095003 doi: 10.1063/1.4962704[473] Alheadary W G, Park K H, Alfaraj N, et al. Free-space optical channel characterization and experimental validation in a coastal environment. Opt Express, 2018, 26, 6614 doi: 10.1364/OE.26.006614[474] de Graaf G, Wolffenbuttel R F. Illumination source identification using a CMOS optical microsystem. IEEE Trans Instrum Meas, 2004, 53, 238 doi: 10.1109/TIM.2003.822476[475] Ji M H, Kim J, Detchprohm T, et al. p–i–p–i–n separate absorption and multiplication ultraviolet avalanche photodiodes. IEEE Photonics Technol Lett, 2018, 30, 181 doi: 10.1109/LPT.2017.2779798[476] Zheng J, Wang L, Wu X, et al. A PMT-like high gain avalanche photodiode based on GaN/AlN periodically stacked structure. Appl Phys Lett, 2016, 109, 241105 doi: 10.1063/1.4972397[477] Li J, Fan Z Y, Dahal R, et al. 200 nm deep ultraviolet photodetectors based on AlN. Appl Phys Lett, 2006, 89, 213510 doi: 10.1063/1.2397021[478] Khan M A, Kuznia J N, Olson D T, et al. High-responsivity photoconductive ultraviolet sensors based on insulating single-crystal GaN epilayers. Appl Phys Lett, 1992, 60, 2917 doi: 10.1063/1.106819[479] Tut T, Biyikli N, Kimukin I, et al. High bandwidth-efficiency solar-blind AlGaN Schottky photodiodes with low dark current. SolidState Electron, 2005, 49, 117 doi: 10.1016/j.sse.2004.07.009[480] Biyikli N, Kimukin I, Kartaloglu T, et al. High-speed solar-blind AlGaN-based metal-semiconductor- metal photodetectors. Phys Status Solidi C, 2003, 0, 2314 doi: 10.1002/pssc.200303518[481] Biyikli N, Aytur O, Kimukin I, et al. Solar-blind AlGaN-based Schottky photodiodes with low noise and high detectivity. Appl Phys Lett, 2002, 81, 3272 doi: 10.1063/1.1516856[482] Pandit B, Cho J. Metal-semiconductor-metal ultraviolet photodiodes based on reduced graphene oxide/GaN Schottky contacts. Thin Solid Films, 2018, 660, 824 doi: 10.1016/j.tsf.2018.03.035[483] Brendel M, Brunner F, Weyers M. On the EQE-bias characteristics of bottom-illuminated AlGaN-based metal–semiconductor–metal photodetectors with asymmetric electrode geometry. J Appl Phys, 2017, 122, 174501 doi: 10.1063/1.4993538[484] Brendel M, Helbling M, Knauer A, et al. Top- and bottom-illumination of solar-blind AlGaN metal-semiconductor-metal photodetectors. Phys Status Solidi A, 2015, 212, 1021 doi: 10.1002/pssa.v212.5[485] Brendel M, Helbling M, Knigge A, et al. Measurement and simulation of top- and bottom-illuminated solar-blind AlGaN metal–semiconductor–metal photodetectors with high external quantum efficiencies. J Appl Phys, 2015, 118, 244504 doi: 10.1063/1.4939283[486] Butun S, Tut T, Butun B, et al. Deep-ultraviolet Al0.75Ga0.25N photodiodes with low cutoff wavelength. Appl Phys Lett, 2006, 88, 123503 doi: 10.1063/1.2186974[487] Narita T, Wakejima A, Egawa T. Ultraviolet photodetectors using transparent gate AlGaN/GaN high electron mobility transistor on silicon substrate. Jpn J Appl Phys, 2013, 52, 01AG06 doi: 10.7567/JJAP.52.01AG06[488] Tut T, Yelboga T, Ulker E, et al. Solar-blind AlGaN-based p–i–n photodetectors with high breakdown voltage and detectivity. Appl Phys Lett, 2008, 92, 103502 doi: 10.1063/1.2895643[489] Teke A, Dogan S, He L, et al. p-GaN-i-GaN/AlGaN multiple-quantum well n-AlGaN back-illuminated ultraviolet detectors. J Electron Mater, 2003, 32, 307 doi: 10.1007/s11664-003-0149-4[490] Collins C J, Chowdhury U, Wong M M, et al. Improved solar-blind detectivity using an Al xGa1– xN heterojunction p–i–n photodiode. Appl Phys Lett, 2002, 80, 3754 doi: 10.1063/1.1480484[491] Wong M M, Chowdhury U, Collins C J, et al. High quantum efficiency AlGaN/GaN solar-blind photodetectors grown by metalorganic chemical vapor deposition. Phys Status Solidi A, 2001, 188, 333 doi: 10.1002/1521-396x(200111)188:1<333::aid-pssa333>3.0.co;2-x[492] Biyikli N, Kimukin I, Kartaloglu T, et al. High-speed solar-blind photodetectors with indium-tin-oxide Schottky contacts. Appl Phys Lett, 2003, 82, 2344 doi: 10.1063/1.1566459[493] Averin S V, Kuznetzov P I, Zhitov V A, et al. Solar-blind MSM-photodetectors based on Al xGa1– xN heterostructures. Opt Quant Electron, 2007, 39, 181 doi: 10.1007/s11082-007-9071-y[494] Wang G, Xie F, Lu H, et al. Performance comparison of front-and back-illuminated AlGaN-based metal–semiconductor–metal solar-blind ultraviolet photodetectors. J Vac Sci Technol B, 2013, 31, 011202 doi: 10.1116/1.4769250[495] Høiaas I M, Liudi Mulyo A, Vullum P E, et al. GaN/AlGaN nanocolumn ultraviolet LED using double-layer graphene as substrate and transparent electrode. Nano Lett, 2019, 19, 1649 doi: 10.1021/acs.nanolett.8b04607[496] Fernández-Garrido S, Ramsteiner M, Gao G, et al. Molecular beam epitaxy of GaN nanowires on epitaxial graphene. Nano Lett, 2017, 17, 5213 doi: 10.1021/acs.nanolett.7b01196[497] Tonkikh A A, Tsebro V I, Obraztsova E A, et al. Films of filled singlewall carbon nanotubes as a new material for high-performance air-sustainable transparent conductive electrodes operating in a wide spectral range. Nanoscale, 2019, 11, 6755 doi: 10.1039/C8NR10238D[498] Boulanger N, Barbero D R. Nanostructured networks of single wall carbon nanotubes for highly transparent, conductive, and anti-reflective flexible electrodes. Appl Phys Lett, 2013, 103, 021116 doi: 10.1063/1.4813498[499] Borges B G A L, Holakoei S, das Neves M F F, et al. Molecular orientation and femtosecond charge transfer dynamics in transparent and conductive electrodes based on graphene oxide and PEDOT:PSS composites. Phys Chem Chem Phys, 2019, 21, 736 doi: 10.1039/C8CP05382K[500] Yan X, Ma J, Xu H, et al. Fabrication of silver nanowires and metal oxide composite transparent electrodes and their application in UV light-emitting diodes. J Phys D, 2016, 49, 325103 doi: 10.1088/0022-3727/49/32/325103[501] Brendel M, Knigge A, Brunner F, et al. Anisotropic responsivity of AlGaN metal-semiconductor-metal photodetectors on epitaxial laterally overgrown AlN/sapphire templates. J Electron Mater, 2014, 43, 833 doi: 10.1007/s11664-013-2955-7[502] Schlegel J, Brendel M, Martens M, et al. Influence of carrier lifetime, transit time, and operation voltages on the photoresponse of visible-blind AlGaN metal–semiconductor–metal photodetectors. Jpn J Appl Phys, 2013, 52, 08JF01 doi: 10.7567/JJAP.52.08JF01[503] Rathkanthiwar S, Kalra A, Muralidharan R, et al. Analysis of screw dislocation mediated dark current in Al0.50Ga0.50N solar-blind metal-semiconductor-metal photodetectors. J Cryst Growth, 2018, 498, 35 doi: 10.1016/j.jcrysgro.2018.05.028[504] Liu H Y, Wang Y H, Hsu W C. Suppression of dark current on AlGaN/GaN metal-semiconductor-metal photodetectors. IEEE Sens J, 2015, 15, 5202 doi: 10.1109/JSEN.2015.2439265[505] Li D, Sun X, Song H, et al. Influence of threading dislocations on GaN-based metal–semiconductor–metal ultraviolet photodetectors. Appl Phys Lett, 2011, 98, 011108 doi: 10.1063/1.3536480[506] Walde S, Brendel M, Zeimer U, et al. Impact of open-core threading dislocations on the performance of AlGaN metal-semiconductor-metal photodetectors. J Appl Phys, 2018, 123, 161551 doi: 10.1063/1.5010859[507] Yoshikawa A, Ushida S, Nagase K, et al. High-performance solar-blind Al0.6Ga0.4N/Al0.5Ga0.5N MSM type photodetector. Appl Phys Lett, 2017, 111, 191103 doi: 10.1063/1.5001979[508] Kang S, Nandi R, Kim H, et al. Synthesis of n-AlGaN nanoflowers by MOCVD for high-performance ultraviolet-C photodetectors. J Mater Chem C, 2018, 6, 1176 doi: 10.1039/C7TC05182D[509] Cicek E, McClintock R, Vashaei Z, et al. Crack-free AlGaN for solar-blind focal plane arrays through reduced area epitaxy. Appl Phys Lett, 2013, 102, 051102 doi: 10.1063/1.4790839[510] Cicek E, Vashaei Z, Huang E Kw, et al. Al xGa1– xN-based deep-ultraviolet 320 × 256 focal plane array. Opt Lett, 2012, 37, 896 doi: 10.1364/OL.37.000896[511] Cicek E, McClintock R, Cho C Y, et al. AlxGa1–xN-based back-illuminated solar-blind photodetectors with external quantum efficiency of 89%. Appl Phys Lett, 2013, 103, 191108 doi: 10.1063/1.4829065[512] Adivarahan V, Simin G, Tamulaitis G, et al. Indium-silicon co-doping of high-aluminum-content AlGaN for solar blind photodetectors. Appl Phys Lett, 2001, 79, 1903 doi: 10.1063/1.1402159[513] Han W Y, Zhang Z W, Li Z M, et al. High performance back-illuminated MIS structure AlGaN solar-blind ultraviolet photodiodes. J Mater Sci Mater Electron, 2018, 29, 9077 doi: 10.1007/s10854-018-8934-2[514] Chen Y, Zhang Z, Jiang H, et al. The optimized growth of AlN templates for back-illuminated AlGaN-based solar-blind ultraviolet photodetectors by MOCVD. J Mater Chem C, 2018, 6, 4936 doi: 10.1039/C8TC00755A[515] Albrecht B, Kopta S, John O, et al. Improved AlGaN p–i–n photodetectors for monitoring of ultraviolet radiation. IEEE J Sel Top Quantum Electron, 2014, 20, 3802507 doi: 10.1109/JSTQE.2014.2326251[516] Ozbay E, Biyikli N, Kimukin I, et al. High-performance solar-blind photodetectors based on AlxGa1– xN heterostructures. IEEE J Sel Top Quantum Electron, 2004, 10, 742 doi: 10.1109/JSTQE.2004.831681[517] Muhtadi S, Hwang S M, Coleman A L, et al. High-speed solar-blind UV photodetectors using high-Al content Al0.64Ga0.36N/ Al0.34Ga0.66N multiple quantum wells. Appl Phys Express, 2017, 10, 011004 doi: 10.7567/APEX.10.011004[518] Babichev A V, Zhang H, Lavenus P, et al. GaN nanowire ultraviolet photodetector with a graphene transparent contact. Appl Phys Lett, 2013, 103, 201103 doi: 10.1063/1.4829756[519] Kang S, Chatterjee U, Um D Y, et al. Ultraviolet-C photodetector fabricated using Si-doped n-AlGaN nanorods grown by MOCVD. ACS Photonics, 2017, 4, 2595 doi: 10.1021/acsphotonics.7b01047[520] Zou Y, Zhang Y, Hu Y, et al. Ultraviolet detectors based on wide bandgap semiconductor nanowire: A review. Sensors, 2018, 18, 2072 doi: 10.3390/s18072072[521] Cai Q, Luo W K, Li Q, et al. AlGaN ultraviolet avalanche photodiodes based on a triple-mesa structure. Appl Phys Lett, 2018, 113, 123503 doi: 10.1063/1.5049621[522] Shao Z G, Chen D J, Lu H, et al. High-gain AlGaN solar-blind avalanche photodiodes. IEEE Electron Device Lett, 2014, 35, 372 doi: 10.1109/LED.2013.2296658[523] Bellotti E, Bertazzi F, Shishehchi S, et al. Theory of carriers transport in III-nitride materials: State of the art and future outlook. IEEE Trans Electron Devices, 2013, 60, 3204 doi: 10.1109/TED.2013.2266577[524] Huang Z, Li J, Zhang W, et al. AlGaN solar-blind avalanche photodiodes with enhanced multiplication gain using back-illuminated structure. Appl Phys Express, 2013, 6, 054101 doi: 10.7567/APEX.6.054101[525] Huang Y, Chen D J, Lu H, et al. Back-illuminated separate absorption and multiplication AlGaN solar-blind avalanche photodiodes. Appl Phys Lett, 2012, 101, 253516 doi: 10.1063/1.4772984[526] Sun L, Chen J, Li J, et al. AlGaN solar-blind avalanche photodiodes with high multiplication gain. Appl Phys Lett, 2010, 97, 191103 doi: 10.1063/1.3515903[527] Dahal R, Al Tahtamouni T M, Lin J Y,et al. AlN avalanche photodetectors. Appl Phys Lett, 2007, 91, 243503 doi: 10.1063/1.2823588[528] Dahal R, Al Tahtamouni T M, Fan Z Y, et al. Hybrid AlN-SiC deep ultraviolet Schottky barrier photodetectors. Appl Phys Lett, 2007, 90, 263505 doi: 10.1063/1.2752126[529] McClintock R, Yasan A, Minder K, et al. Avalanche multiplication in AlGaN based solar-blind photodetectors. Appl Phys Lett, 2005, 87, 241123 doi: 10.1063/1.2140610[530] Nikzad S, Hoenk M, Jewell A, et al. Single photon counting UV solar-blind detectors using silicon and III–nitride materials. Sensors, 2016, 16, 927 doi: 10.3390/s16060927[531] Pau J L, McClintock R, Minder K, et al. Geiger-mode operation of back-illuminated GaN avalanche photodiodes. Appl Phys Lett, 2007, 91, 041104 doi: 10.1063/1.2759980[532] Kim J, Ji M H, Detchprohm T, et al. Comparison of AlGaN p–i–n ultraviolet avalanche photodiodes grown on free-standing GaN and sapphire substrates. Appl Phys Express, 2015, 8, 122202 doi: 10.7567/APEX.8.122202[533] Wu H, Wu W, Zhang H, et al. All AlGaN epitaxial structure solar-blind avalanche photodiodes with high efficiency and high gain. Appl Phys Express, 2016, 9, 052103 doi: 10.7567/APEX.9.052103[534] Hahn L, Fuchs F, Kirste L, et al. Avalanche multiplication in AlGaN-based heterostructures for the ultraviolet spectral range. Appl Phys Lett, 2018, 112, 151102 doi: 10.1063/1.5022660[535] Shao Z, Chen D, Liu Y, et al. Significant performance improvement in AlGaN solar-blind avalanche photodiodes by exploiting the built-in polarization electric field. IEEE J Sel Top Quantum Electron, 2014, 20, 3803306 doi: 10.1109/JSTQE.2014.2328437[536] Walker D, Kumar V, Mi K, et al. Solar-blind AlGaN photodiodes with very low cutoff wavelength. Appl Phys Lett, 2000, 76, 403 doi: 10.1063/1.125768[537] Gökkavas M, Butun S, Tut T, et al. AlGaN-based high-performance metal-semiconductor-metal photodetectors. Photonics Nanostruct: Fundam Appl, 2007, 5, 53 doi: 10.1016/j.photonics.2007.06.002[538] Izyumskaya N, Demchenko D O, Das S, et al. Recent development of boron nitride towards electronic applications. Adv Electron Mater, 2017, 3, 1600485 doi: 10.1002/aelm.201600485[539] Monroy E, Omnès F, Calle F. Wide-bandgap semiconductor ultraviolet photodetectors. Semicond Sci Technol, 2003, 18, R33 doi: 10.1088/0268-1242/18/4/201[540] Munoz E, Monroy E, Pau J, et al. III nitrides and UV detection. J Phys Condens Matter, 2001, 13, 7115 doi: 10.1088/0953-8984/13/32/316[541] Rodak L, Sampath A, Gallinat C, et al. Solar-blind AlxGa1– xN/ AlN/SiC photodiodes with a polarization-induced electron filter. Appl Phys Lett, 2013, 103, 071110 doi: 10.1063/1.4818551[542] Spies M, Den Hertog M I, Hille P, et al. Bias-controlled spectral response in GaN/AlN single-nanowire ultraviolet photodetectors. Nano Lett, 2017, 17, 4231 doi: 10.1021/acs.nanolett.7b01118[543] Nikishin S, Borisov B, Pandikunta M, et al. High quality AlN for deep UV photodetectors. Appl Phys Lett, 2009, 95, 054101 doi: 10.1063/1.3200229[544] Barkad H A, Soltani A, Mattalah M, et al. Design, fabrication and physical analysis of TiN/AlN deep UV photodiodes. J Phys D, 2010, 43, 465104 doi: 10.1088/0022-3727/43/46/465104[545] Laksana C P, Chen M R, Liang Y, et al. Deep-UV sensors based on SAW oscillators using low-temperature-grown AlN films on sapphires. IEEE Trans Ultrason Ferroelectr Freq Control, 2011, 58, 1688 doi: 10.1109/TUFFC.2011.1997[546] Soltani A, Barkad H, Mattalah M, et al. 193 nm deep-ultraviolet solar-blind cubic boron nitride based photodetectors. Appl Phys Lett, 2008, 92, 053501 doi: 10.1063/1.2840178[547] Li J, Majety S, Dahal R, et al. Dielectric strength, optical absorption, and deep ultraviolet detectors of hexagonal boron nitride epilayers. Appl Phys Lett, 2012, 101, 171112 doi: 10.1063/1.4764533[548] Yang N, Zeng X, Lu J, et al. Effect of chemical functionalization on the thermal conductivity of 2D hexagonal boron nitride. Appl Phys Lett, 2018, 113, 171904 doi: 10.1063/1.5050293[549] Sajjad M, Jadwisienczak W M, Feng P. Nanoscale structure study of boron nitride nanosheets and development of a deep-UV photo-detector. Nanoscale, 2014, 6, 4577 doi: 10.1039/C3NR05817D[550] Liu H, Meng J, Zhang X, et al. High-performance deep ultraviolet photodetectors based on few-layer hexagonal boron nitride. Nanoscale, 2018, 10, 5559 doi: 10.1039/C7NR09438H[551] Alfaraj N, Li K H, Kang C H, et al. Electrical characterization of solar-blind deep-ultraviolet (Al0.28Ga0.72)2O3 Schottky photodetectors grown on silicon by pulsed laser deposition. Conference on Lasers and Electro–Optics, 2019[552] Tian H, Liu Q, Hu A, et al. Hybrid graphene/GaN ultraviolet photo-transistors with high responsivity and speed. Opt Express, 2018, 26, 5408 doi: 10.1364/OE.26.005408[553] Tian H, Liu Q, Zhou C, et al. Hybrid graphene/unintentionally doped GaN ultraviolet photodetector with high responsivity and speed. Appl Phys Lett, 2018, 113, 121109 doi: 10.1063/1.5034527[554] Seo T H, Lee K J, Park A H, et al. Enhanced light output power of near UV light emitting diodes with graphene/indium tin oxide nanodot nodes for transparent and current spreading electrode. Opt Express, 2011, 19, 23111 doi: 10.1364/OE.19.023111[555] Li K H, Alfaraj N, Kang C H, et al. Deep-ultraviolet β-Ga2O3 photodetectors grown on MgO substrates with a TiN template. 2019 IEEE Photonics Conference (IPC), San Antonio, TX, United States, 2019[556] Qian L X, Liu H Y, Zhang H F, et al. Simultaneously improved sensitivity and response speed of β-Ga2O3 solar-blind photodetector via localized tuning of oxygen deficiency. Appl Phys Lett, 2019, 114, 113506 doi: 10.1063/1.5088665[557] Xu Y, An Z, Zhang L, et al. Solar blind deep ultraviolet β-Ga2O3 photodetectors grown on sapphire by the Mist-CVD method. Opt Mater Express, 2018, 8, 2941 doi: 10.1364/OME.8.002941[558] Rathkanthiwar S, Kalra A, Solanke S V, et al. Gain mechanism and carrier transport in high responsivity AlGaN-based solar blind metal semiconductor metal photodetectors. J Appl Phys, 2017, 121, 164502 doi: 10.1063/1.4982354[559] Zhuo R, Zeng L, Yuan H, et al. In-situ fabrication of PtSe2/GaN heterojunction for self-powered deep ultraviolet photodetector with ultrahigh current on/off ratio and detectivity. Nano Res, 2019, 12, 183 doi: 10.1007/s12274-018-2200-z[560] Zhuo R, Wang Y, Wu D, et al. High-performance self-powered deep ultraviolet photodetector based on MoS2/GaN p-n heterojunction. J Mater Chem C, 2018, 6, 299 doi: 10.1039/C7TC04754A[561] He T, Zhao Y, Zhang X, et al. Solar-blind ultraviolet photodetector based on graphene/vertical Ga2O3 nanowire array heterojunction. Nanophotonics, 2018, 7, 1557 doi: 10.1515/nanoph-2018-0061[562] Lin R, Zheng W, Zhang D, et al. High-performance graphene/β-Ga2O3 heterojunction deep-ultraviolet photodetector with hot-electron excited carrier multiplication. ACS Appl Mater Interfaces, 2018, 10, 22419 doi: 10.1021/acsami.8b05336[563] Lu Y, Wu Z, Xu W, et al. ZnO quantum dot-doped graphene/h-BN/GaN-heterostructure ultraviolet photodetector with extremely high responsivity. Nanotechnology, 2016, 27, 48LT03 doi: 10.1088/0957-4484/27/48/48LT03[564] Ai M, Guo D, Qu Y, et al. Fast-response solar-blind ultraviolet photodetector with a graphene/β-Ga2O3/graphene hybrid structure. J Alloys Compd, 2017, 692, 634 doi: 10.1016/j.jallcom.2016.09.087[565] Kumar M, Jeong H, Polat K, et al. Fabrication and characterization of graphene/AlGaN/GaN ultraviolet Schottky photodetector. J Phys D , 2016, 49, 275105 doi: 10.1088/0022-3727/49/27/275105[566] Martens M, Mehnke F, Kuhn C, et al. Performance characteristics of UV-C AlGaN-based lasers grown on sapphire and bulk AlN substrates. IEEE Photonics Technol Lett, 2014, 26, 342 doi: 10.1109/LPT.2013.2293611[567] Xie J, Mita S, Bryan Z, et al. Lasing and longitudinal cavity modes in photo-pumped deep ultraviolet AlGaN heterostructures. Appl Phys Lett, 2013, 102, 171102 doi: 10.1063/1.4803689[568] Wunderer T, Chua C, Northrup J, et al. Optically pumped UV lasers grown on bulk AlN substrates. Phys Status Solidi C, 2012, 9, 822 doi: 10.1002/pssc.201100424[569] Jmerik V N, Mizerov A M, Shubina T V, et al. Optically pumped lasing at 300.4 nm in AlGaN MQW structures grown by plasmaassisted molecular beam epitaxy on c-Al2O3. Phys Status Solidi A, 2010, 207, 1313 doi: 10.1002/pssa.200983612[570] Takano T, Narita Y, Horiuchi A, et al. Room-temperature deep-ultraviolet lasing at 241.5 nm of AlGaN multiple-quantum-well laser. Appl Phys Lett, 2004, 84, 3567 doi: 10.1063/1.1737061[571] Martens M, Kuhn C, Simoneit T, et al. The effects of magnesium doping on the modal loss in AlGaN-based deep UV lasers. Appl Phys Lett, 2017, 110, 081103 doi: 10.1063/1.4977029[572] Pecora E F, Sun H, Dal Negro L, et al. Deep-UV optical gain in AlGaN-based graded-index separate confinement heterostructure. Opt Mater Express, 2015, 5, 809 doi: 10.1364/OME.5.000809[573] Zhu H, Shan C X, Li B H, et al. Low-threshold electrically pumped ultraviolet laser diode. J Mater Chem, 2011, 21, 2848 doi: 10.1039/c0jm04233a[574] Yoshida H, Yamashita Y, Kuwabara M, et al. A 342-nm ultraviolet AlGaN multiple-quantum-well laser diode. Nat Photonics, 2008, 2, 551 doi: 10.1038/nphoton.2008.135[575] Sellés J, Brimont C, Cassabois G, et al. Deep-UV nitride-on-silicon microdisk lasers. Sci Rep, 2016, 6, 21650 doi: 10.1038/srep21650[576] Zhao S, Mi Z. AlGaN nanowires: Path to electrically injected semiconductor deep ultraviolet lasers. IEEE J Quantum Electron, 2018, 54, 2001009 doi: 10.1109/JQE.2018.2870439[577] Zhao S, Liu X, Wu Y, et al. An electrically pumped 239 nm AlGaN nanowire laser operating at room temperature. Appl Phys Lett, 2016, 109, 191106 doi: 10.1063/1.4967180[578] Zhao S, Liu X, Woo S, et al. An electrically injected AlGaN nanowire laser operating in the ultraviolet-C band. Appl Phys Lett, 2015, 107, 043101 doi: 10.1063/1.4927602[579] Pan R, Retzer U, Werblinski T, et al. Generation of high-energy, kilohertz-rate narrowband tunable ultraviolet pulses using a burst-mode dye laser system. Opt Lett, 2018, 43, 1191 doi: 10.1364/OL.43.001191[580] Higase Y, Morita S, Fujii T, et al. High-gain and wide-band optical amplifications induced by a coupled excited state of organic dye molecules co-doped in polymer waveguide. Opt Lett, 2018, 43, 1714 doi: 10.1364/OL.43.001714[581] Yamamoto H, Oyamada T, Sasabe H, et al. Amplified spontaneous emission under optical pumping from an organic semiconductor laser structure equipped with transparent carrier injection electrodes. Appl Phys Lett, 2004, 84, 1401 doi: 10.1063/1.1646730[582] Tsutsumi N, Kawahira T, Sakai W. Amplified spontaneous emission and distributed feedback lasing from a conjugated compound in various polymer matrices. Appl Phys Lett, 2003, 83, 2533 doi: 10.1063/1.1614834[583] Kogelnik H, Shank C V. Stimulated emission in a periodic structure. Appl Phys Lett, 1971, 18, 152 doi: 10.1063/1.1653605[584] Lochner Z, Kao T T, Liu Y S, et al. Deep-ultraviolet lasing at 243 nm from photo-pumped AlGaN/AlN heterostructure on AlN substrate. Appl Phys Lett, 2013, 102, 101110 doi: 10.1063/1.4795719[585] Kao T T, Liu Y S, Satter M M, et al. Sub-250 nm low-threshold deep-ultraviolet AlGaN-based heterostructure laser employing HfO2/SiO2 dielectric mirrors. Appl Phys Lett, 2013, 103, 211103 doi: 10.1063/1.4829477[586] Shatalov M, Gaevski M, Adivarahan V, et al. Room-temperature stimulated emission from AlN at 214 nm. J Appl Phys, 2006, 45, L1286 doi: 10.1143/JJAP.45.L1286[587] Klein T, Klembt S, Kozlovsky V, et al. High-power green and blue electron-beam pumped surface-emitting lasers using dielectric and epitaxial distributed Bragg reflectors. J Appl Phys, 2015, 117, 113106 doi: 10.1063/1.4915625[588] Oto T, Banal R G, Kataoka K, et al. 100 mW deep-ultraviolet emission from aluminium-nitride-based quantum wells pumped by an electron beam. Nat Photonics, 2010, 4, 767 doi: 10.1038/nphoton.2010.220[589] Demir I, Li H, Robin Y, et al. Sandwich method to grow high quality AlN by MOCVD. J Phys D, 2018, 51, 085104 doi: 10.1088/1361-6463/aaa926[590] Tran B T, Hirayama H, Jo M, et al. High-quality AlN template grown on a patterned Si(111) substrate. J Cryst Growth, 2017, 468, 225 doi: 10.1016/j.jcrysgro.2016.12.100[591] Kataoka K, Funato M, Kawakami Y. Development of polychromatic ultraviolet light-emitting diodes based on three-dimensional AlGaN quantum wells. Appl Phys Express, 2017, 10, 121001 doi: 10.7567/APEX.10.121001[592] Kataoka K, Funato M, Kawakami Y. Deep-ultraviolet polychromatic emission from three-dimensionally structured AlGaN quantum wells. Appl Phys Express, 2017, 10, 031001 doi: 10.7567/APEX.10.031001[593] Funato M, Hayashi K, Ueda M, et al. Emission color tunable light-emitting diodes composed of InGaN multifacet quantum wells. Appl Phys Lett, 2008, 93, 021126 doi: 10.1063/1.2956404[594] Kaneda M, Pernot C, Nagasawa Y, et al. Uneven AlGaN multiple quantum well for deep-ultraviolet LEDs grown on macrosteps and impact on electroluminescence spectral output. Jpn J Appl Phys, 2017, 56, 061002 doi: 10.7567/JJAP.56.061002[595] Pernot C, Fukahori S, Inazu T, et al. Development of high efficiency 255–355 nm AlGaN-based light-emitting diodes. Phys Status Solidi A, 2011, 208, 1594 doi: 10.1002/pssa.201001037[596] Pernot C, Kim M, Fukahori S, et al. Improved efficiency of 255–280 nm AlGaN-based light-emitting diodes. Appl Phys Express, 2010, 3, 061004 doi: 10.1143/APEX.3.061004[597] Nagamatsu K, Okada N, Sugimura H, et al. High-efficiency AlGaN-based UV light-emitting diode on laterally overgrown AlN. J Cryst Growth, 2008, 310, 2326 doi: 10.1016/j.jcrysgro.2007.11.152[598] Harada T, Oda Y, Motohisa J, et al. Novel nanofaceting structures grown on patterned vicinal (110) GaAs substrates by metal-organic vapor phase epitaxy (MOVPE). Jpn J Appl Phys, 2000, 39, 7090 doi: 10.1143/JJAP.39.7090[599] Oda Y, Fukui T. Natural formation of multiatomic steps on patterned vicinal substrates by MOVPE and application to GaAs QWR structures. J Cryst Growth, 1998, 195, 6 doi: 10.1016/S0022-0248(98)00647-2[600] Susilo N, Hagedorn S, Jaeger D, et al. AlGaN-based deep UV LEDs grown on sputtered and high temperature annealed AlN/sapphire. Appl Phys Lett, 2018, 112, 041110 doi: 10.1063/1.5010265[601] He C, Zhao W, Wu H, et al. High-quality AlN film grown on sputtered AlN/sapphire via growth-mode modification. Cryst Growth Des, 2018, 18, 6816 doi: 10.1021/acs.cgd.8b01045[602] Xiao S, Suzuki R, Miyake H, et al. Improvement mechanism of sputtered AlN films by high-temperature annealing. J Cryst Growth, 2018, 502, 41 doi: 10.1016/j.jcrysgro.2018.09.002[603] Zhao L, Yang K, Ai Y, et al. Crystal quality improvement of sputtered AlN film on sapphire substrate by high-temperature annealing. J Mater Sci Mater Electron, 2018, 29, 13766 doi: 10.1007/s10854-018-9507-0[604] Ben J, Sun X, Jia Y, et al. Defect evolution in AlN templates on PVD-AlN/sapphire substrates by thermal annealing. Cryst Eng Comm, 2018, 20, 4623 doi: 10.1039/C8CE00770E[605] Zhao L, Zhang S, Zhang Y, et al. AlGaN-based ultraviolet light-emitting diodes on sputter-deposited AlN templates with epitaxial AlN/AlGaN superlattices. Superlattices Microstruct, 2018, 113, 713 doi: 10.1016/j.spmi.2017.12.003[606] Oh J T, Moon Y T, Kang D S, et al. High efficiency ultraviolet GaN-based vertical light emitting diodes on 6-inch sapphire substrate using ex-situ sputtered AlN nucleation layer. Opt Express, 2018, 26, 5111 doi: 10.1364/OE.26.005111[607] He C, Zhao W, Zhang K, et al. High-quality GaN epilayers achieved by facet-controlled epitaxial lateral overgrowth on sputtered AlN/PSS templates. ACS Appl Mater Interfaces, 2017, 9, 43386 doi: 10.1021/acsami.7b14801[608] Chen Z, Zhang J, Xu S, et al. Influence of stacking faults on the quality of GaN films grown on sapphire substrate using a sputtered AlN nucleation layer. Mater Res Bull, 2017, 89, 193 doi: 10.1016/j.materresbull.2016.12.023[609] Chen Z, Zhang J, Xu S, et al. Effect of AlN interlayer on the impurity incorporation of GaN film grown on sputtered AlN. J Alloys Compd, 2017, 710, 756 doi: 10.1016/j.jallcom.2017.03.217[610] Zhang L, Xu F, Wang M, et al. High-quality AlN epitaxy on sapphire substrates with sputtered buffer layers. Superlattices Microstruct, 2017, 105, 34 doi: 10.1016/j.spmi.2017.03.013[611] Yoshizawa R, Miyake H, Hiramatsu K. Effect of thermal annealing on AlN films grown on sputtered AlN templates by metalorganic vapor phase epitaxy. Jpn J Appl Phys, 2017, 57, 01AD05 doi: 10.7567/JJAP.57.01AD05[612] Funato M, Shibaoka M, Kawakami Y. Heteroepitaxy mechanisms of AlN on nitridated c-and a-plane sapphire substrates. J Appl Phys, 2017, 121, 085304 doi: 10.1063/1.4977108[613] Okada N, Kato N, Sato S, et al. Growth of high-quality and crack free AlN layers on sapphire substrate by multi-growth mode modification. J Cryst Growth, 2007, 298, 349 doi: 10.1016/j.jcrysgro.2006.10.123[614] Chang H, Chen Z, Li W, et al. Graphene-assisted quasi-van der Waals epitaxy of AlN film for ultraviolet light emitting diodes on nano-patterned sapphire substrate. Appl Phys Lett, 2019, 114, 091107 doi: 10.1063/1.5081112[615] Zhang L, Li X, Shao Y, Yu J, et al. Improving the quality of GaN crystals by using graphene or hexagonal boron nitride nanosheets substrate. ACS Appl Mater Interfaces, 2015, 7, 4504 doi: 10.1021/am5087775[616] Kim J, Bayram C, Park H, et al. Principle of direct van der Waals epitaxy of single-crystalline films on epitaxial graphene. Nat Commun, 2014, 5, 4836 doi: 10.1038/ncomms5836[617] Han N, Cuong T V, Han M, et al. Improved heat dissipation in gallium nitride light-emitting diodes with embedded graphene oxide pattern. Nat Commun, 2013, 4, 1452 doi: 10.1038/ncomms2448[618] Roy R, Hill V G, Osborn E F. Polymorphism of Ga2O3 and the system Ga2O3–H2O. J Am Chem Soc, 1952, 74, 719 doi: 10.1021/ja01123a039[619] Han S H, Mauze A, Ahmadi E, et al. n-type dopants in (001) β-Ga2O3 grown on (001) β-Ga2O3 substrates by plasma-assisted molecular beam epitaxy. Semicond Sci Technol, 2018, 33, 045001 doi: 10.1088/1361-6641/aaae56[620] Sasaki K, Kuramata A, Masui T, et al. Device-quality β-Ga2O3 epitaxial films fabricated by ozone molecular beam epitaxy. Appl Phys Express, 2012, 5, 035502 doi: 10.1143/APEX.5.035502[621] Shimamura K, Víllora E G, Domen K, et al. Epitaxial growth of GaN on (100) β-Ga2O3 substrates by metalorganic vapor phase epitaxy. Jpn J Appl Phys, 2005, 44, L7 doi: 10.1143/JJAP.44.L7[622] Víllora E G, Shimamura K, Aoki K, et al. Molecular beam epitaxy of c-plane wurtzite GaN on nitridized a-plane β-Ga2O3. Thin Solid Films, 2006, 500, 209 doi: 10.1016/j.tsf.2005.10.080[623] Ohira S, Suzuki N, Minami H, et al. Growth of hexagonal GaN films on the nitridated β-Ga2O3 substrates using RF-MBE. Phys Status Solidi C, 2007, 4, 2306 doi: 10.1002/pssc.200674877[624] Kachel K, Korytov M, Gogova D, et al. A new approach to free-standing GaN using β-Ga2O3 as a substrate. Cryst Eng Comm, 2012, 14, 8536 doi: 10.1039/c2ce25976a[625] Ito S, Takeda K, Nagata K, et al. Growth of GaN and AlGaN on (100) β-Ga2O3 substrates. Phys Status Solidi C, 2012, 9, 519 doi: 10.1002/pssc.201100499[626] Ajia I A, Yamashita Y, Lorenz K, et al. GaN/AlGaN multiple quantum wells grown on transparent and conductive (-201)-oriented β-Ga2O3 substrate for UV vertical light emitting devices. Appl Phys Lett, 2018, 113, 082102 doi: 10.1063/1.5025178[627] Yamada K, Nagasawa Y, Nagai S, et al. Study on the main-chain structure of amorphous fluorine resins for encapsulating AlGaN-based DUV-LEDs. Phys Status Solidi A, 2018, 215, 1700525 doi: 10.1002/pssa.201700525[628] Nagai S, Yamada K, Hirano A, et al. Development of highly durable deep-ultraviolet AlGaN-based LED multichip array with hemispherical encapsulated structures using a selected resin through a detailed feasibility study. Jpn J Appl Phys, 2016, 55, 082101 doi: 10.7567/JJAP.55.082101[629] Liang R, Dai J, Xu L, et al. Interface anchored effect on improving working stability of deep ultraviolet light-emitting diode using graphene oxide-based fluoropolymer encapsulant. ACS Appl Mater Interfaces, 2018, 10, 8238 doi: 10.1021/acsami.7b17668[630] Shen K C, Ku C T, Hsieh C, et al. Deep-ultraviolet hyperbolic metacavity laser. Adv Mater, 2018, 30, 1706918 doi: 10.1002/adma.v30.21[631] Shen K C, Hsieh C, Cheng Y J, et al. Giant enhancement of emission efficiency and light directivity by using hyperbolic metacavity on deep-ultraviolet AlGaN emitter. Nano Energy, 2018, 45, 353 doi: 10.1016/j.nanoen.2018.01.020[632] Tangi M, Mishra P, Tseng C C, et al. Band alignment at GaN/single-layer WSe2 interface. ACS Appl Mater Interfaces, 2017, 9, 9110 doi: 10.1021/acsami.6b15370[633] Mishra P, Tangi M, Ng T K, et al. Impact of N-plasma and Ga-irradiation on MoS2 layer in molecular beam epitaxy. Appl Phys Lett, 2017, 110, 012101 doi: 10.1063/1.4973371[634] Zhao C, Ng T K, Tseng C C, et al. InGaN/GaN nanowires epitaxy on large-area MoS2 for high-performance light-emitters. RSC Adv, 2017, 7, 26665 doi: 10.1039/C7RA03590J[635] Tangi M, Mishra P, Li M Y, et al. Type-I band alignment at MoS2/In0.15Al0.85N lattice matched heterojunction and realization of MoS2 quantum well. Appl Phys Lett, 2017, 111, 092104 doi: 10.1063/1.4995976[636] Tangi M, Mishra P, Ng T K, et al. Determination of band offsets at GaN/single-layer MoS2 heterojunction. Appl Phys Lett, 2016, 109, 032104 doi: 10.1063/1.4959254[637] Gupta P, Rahman A, Subramanian S, et al. Layered transition metal dichalcogenides: Promising near-lattice-matched substrates for GaN growth. Sci Rep, 2016, 6, 23708 doi: 10.1038/srep23708[638] Lopez-Sanchez O, Lembke D, Kayci M, et al. Ultrasensitive photodetectors based on monolayer MoS2. Nat Nanotech, 2013, 8, 497 doi: 10.1038/nnano.2013.100[639] Yin Z, Li H, Li H, Jiang L, et al. Single-layer MoS2 phototransistors. ACS Nano, 2011, 6, 74 doi: 10.1021/nn2024557[640] Saigal N, Wielert I, Čapeta D, et al. Effect of lithium doping on the optical properties of monolayer MoS2. Appl Phys Lett, 2018, 112, 121902 doi: 10.1063/1.5021629[641] Splendiani A, Sun L, Zhang Y, et al. Emerging photoluminescence in monolayer MoS2. Nano Lett, 2010, 10, 1271 doi: 10.1021/nl903868w[642] Mak K F, Lee C, Hone J, et al. Atomically thin MoS2: A new direct-gap semiconductor. Phys Rev Lett, 2010, 105, 136805 doi: 10.1103/PhysRevLett.105.136805[643] Bharathi N D, Sivasankaran K. Research progress and challenges of two dimensional MoS2 field effect transistors. J Semicond, 2018, 39, 104002 doi: 10.1088/1674-4926/39/10/104002[644] Pak Y, Kim Y, Lim N, et al. Scalable integration of periodically aligned 2D-MoS2 nanoribbon array. APL Mater, 2018, 6, 076102 doi: 10.1063/1.5038823[645] Huang C Y, Chang C, Lu G Z, et al. Hybrid 2D/3D MoS2/GaN heterostructures for dual functional photoresponse. Appl Phys Lett, 2018, 112, 233106 doi: 10.1063/1.5030537[646] Grisafe B, Zhao R, Ghosh R K, et al. Electrically triggered insulator-to-metal phase transition in two-dimensional (2D) heterostructures. Appl Phys Lett, 2018, 113, 142101 doi: 10.1063/1.5044185[647] Ahmad M, Varandani D, Mehta B R. Large surface charge accumulation in 2D MoS2/Sb2Te3 junction and its effect on junction properties: KPFM based study. Appl Phys Lett, 2018, 113, 141603 doi: 10.1063/1.5042499[648] Roy K, Padmanabhan M, Goswami S, et al. Graphene-MoS2 hybrid structures for multifunctional photoresponsive memory devices. Nat Nanotech, 2013, 8, 826 doi: 10.1038/nnano.2013.206[649] Wang Q H, Kalantar-Zadeh K, Kis A, et al. Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nat Nanotech, 2012, 7, 699 doi: 10.1038/nnano.2012.193[650] Wang L, Jie J, Shao Z, et al. MoS2/Si heterojunction with vertically standing layered structure for ultrafast, high-detectivity, self-driven visible-near infrared photodetectors. Adv Funct Mater, 2015, 25, 2910 doi: 10.1002/adfm.201500216[651] Zhao C, Ng T K, ElAfandy R T, et al. Droop-free, reliable, and high-power InGaN/GaN nanowire light-emitting diodes for monolithic metal-optoelectronics. Nano Lett, 2016, 16, 4616 doi: 10.1021/acs.nanolett.6b01945[652] Li L, Zhang Y, Xu S, et al. On the hole injection for III-nitride based deep ultraviolet light-emitting diodes. Materials, 2017, 10, 1221 doi: 10.3390/ma10101221[653] Tangi M, Kuyyalil J, Shivaprasad S M. Optical bandgap and near surface band bending in degenerate InN films grown by molecular beam epitaxy. J Appl Phys, 2013, 114, 153501 doi: 10.1063/1.4824823[654] Kuyyalil J, Tangi M, Shivaprasad S. Effect of interfacial lattice mismatch on bulk carrier concentration and band gap of InN. J Appl Phys, 2012, 112, 083521 doi: 10.1063/1.4759449[655] Roul B, Kumar M, Rajpalke M K, et al. Binary group III-nitride based heterostructures: band offsets and transport properties. J Phys D, 2015, 48, 423001 doi: 10.1088/0022-3727/48/42/423001[656] Zubair A, Nourbakhsh A, Hong J Y, et al. Hot electron transistor with van der Waals base-collector heterojunction and highperformance GaN emitter. Nano Lett, 2017, 17, 3089 doi: 10.1021/acs.nanolett.7b00451[657] Liu J, Kobayashi A, Toyoda S, et al. Band offsets of polar and nonpolar GaN/ZnO heterostructures determined by synchrotron radiation photoemission spectroscopy. Phys Status Solidi B, 2011, 248, 956 doi: 10.1002/pssb.v248.4[658] King P D C, Veal T D, Kendrick C E, et al. InN/GaN valence band offset: High-resolution X-ray photoemission spectroscopy measurements. Phys Rev B, 2008, 78, 033308 doi: 10.1103/PhysRevB.78.033308[659] King P D C, Veal T D, Jefferson P H, et al. Valence band offset of InN/AlN heterojunctions measured by X-ray photoelectron spectroscopy. Appl Phys Lett, 2007, 90, 132105 doi: 10.1063/1.2716994[660] Martin G, Botchkarev A, Rockett A, et al. Valence-band discontinuities of wurtzite GaN, AlN, and InN heterojunctions measured by X-ray photoemission spectroscopy. Appl Phys Lett, 1996, 68, 2541 doi: 10.1063/1.116177[661] Mietze C, Landmann M, Rauls E, et al. Band offsets in cubic GaN/AlN superlattices. Phys Rev B, 2011, 83, 195301 doi: 10.1103/PhysRevB.83.195301[662] Sang L, Zhu Q S, Yang S Y, et al. Band offsets of non-polar A-plane GaN/AlN and AlN/GaN heterostructures measured by X-ray photoemission spectroscopy. Nanoscale Res Lett, 2014, 9, 470 doi: 10.1186/1556-276X-9-470[663] Zhao G, Li H, Wang L, et al. Measurement of semi-polar (11-22) plane AlN/GaN heterojunction band offsets by X-ray photoelectron spectroscopy. Appl Phys A, 2018, 124, 130 doi: 10.1007/s00339-018-1561-1[664] Mahmood Z H, Shah A P, Kadir A, et al. Determination of InN- GaN heterostructure band offsets from internal photoemission measurements. Appl Phys Lett, 2007, 91, 152108 doi: 10.1063/1.2794788[665] Wu C L, Lee H M, Kuo C T, et al. Polarization-induced valence-band alignments at cation- and anion-polar InN/GaN heterojunctions. Appl Phys Lett, 2007, 91, 042112 doi: 10.1063/1.2764448[666] Shih C F, Chen N C, Chang P H, et al. Band offsets of InN/GaN interface. Jpn J Appl Phys, 2005, 44, 7892 doi: 10.1143/JJAP.44.7892[667] Wang K, Lian C, Su N, et al. Conduction band offset at the InN/GaN heterojunction. Appl Phys Lett, 2007, 91, 232117 doi: 10.1063/1.2821378[668] Shibin K T C, Gupta G. Band alignment and Schottky behaviour of InN/GaN heterostructure grown by low-temperature low-energy nitrogen ion bombardment. RSC Adv, 2014, 4, 27308 doi: 10.1039/C4RA02533D[669] Akazawa M, Gao B, Hashizume T, et al. Measurement of valence-band offsets of InAlN/GaN heterostructures grown by metal-organic vapor phase epitaxy. J Appl Phys, 2011, 109, 013703 doi: 10.1063/1.3527058[670] Jiao W, Kong W, Li J, et al. Characterization of MBE-grown InAlN/GaN heterostructure valence band offsets with varying In composition. AIP Adv, 2016, 6, 035211 doi: 10.1063/1.4944502[671] Ekpunobi A J, Animalu A O E. Band offsets and properties of AlGaAs/GaAs and AlGaN/GaN material systems. Superlattices Microstruct, 2002, 31, 247 doi: 10.1006/spmi.2002.1042[672] Sun H, Park Y J, Li K H, et al. Nearly-zero valence band and large conduction band offset at BAlN/GaN heterointerface for optical and power device application. Appl Surf Sci, 2018, 458, 949 doi: 10.1016/j.apsusc.2018.07.178[673] Sun H, Park Y J, Li K H, et al. Band alignment of B0.14Al0.86N/ Al0.7Ga0.3N heterojunction. Appl Phys Lett, 2017, 111, 122106 doi: 10.1063/1.4999249[674] Fares C, Tadjer M J, Woodward J, et al. Valence and conduction band offsets for InN and III-nitride ternary alloys on (−201) bulk β-Ga2O3. ECS J Solid State Sci Technol, 2019, 8, Q3154 doi: 10.1149/2.0281907jss[675] Carey IV P H, Ren F, Hays D C, et al. Band offsets in ITO/Ga2O3 heterostructures. Appl Surf Sci, 2017, 422, 179 doi: 10.1016/j.apsusc.2017.05.262[676] Fares C, Ren F, Lambers E, et al. Valence and conduction band offsets for sputtered AZO and ITO on (010) (Al0.14Ga0.86)2O3. Semicond Sci Technol, 2019, 34, 025006 doi: 10.1088/1361-6641/aaf8d7[677] Fares C, Ren F, Lambers E, et al. Valence- and conduction-band offsets for atomiclayer-deposited Al2O3 on (010) (Al0.14Ga0.86)2O3. J Electron Mater, 2019, 48, 1568 doi: 10.1007/s11664-018-06885-x[678] Liu J M, Liu X L, Xu X Q, et al. Measurement of w-InN/h-BN heterojunction band offsets by X-ray photoemission spectroscopy. Nanoscale Res Lett, 2010, 5, 1340 doi: 10.1007/s11671-010-9650-x[679] Zhang Z H, Zhang Y, Bi W, et al. On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates. Phys Status Solidi A, 2016, 213, 3078 doi: 10.1002/pssa.201600281[680] Karpov S. ABC-model for interpretation of internal quantum efficiency and its droop in III-nitride LEDs: a review. Opt Quantum Electron, 2015, 47, 1293 doi: 10.1007/s11082-014-0042-9[681] Bayerl M W, Brandt M S, Graf T, et al. g values of effective mass donors in Al xGa1– xN alloys. Phys Rev B, 2001, 63, 165204 doi: 10.1103/PhysRevB.63.165204[682] McGill S A, Cao K, Fowler W B, et al. Bound-polaron model of effective-mass binding energies in GaN. Phys Rev B, 1998, 57, 8951 doi: 10.1103/PhysRevB.57.8951[683] Im J S, Moritz A, Steuber F, et al. Radiative carrier lifetime, momentum matrix element, and hole effective mass in GaN. Appl Phys Lett, 1997, 70, 631 doi: 10.1063/1.118293[684] Hirayama H, Tsukada Y, Maeda T, et al. Marked enhancement in the efficiency of deep-ultraviolet AlGaN light-emitting diodes by using a multiquantum-barrier electron blocking layer. Appl Phys Express, 2010, 3, 031002 doi: 10.1143/APEX.3.031002[685] Hirayama H. Quaternary InAlGaN-based high-efficiency ultraviolet light-emitting diodes. J Appl Phys, 2005, 97, 091101 doi: 10.1063/1.1899760[686] Müβener, Teubert J, Hille P, et al. Probing the internal electric field in GaN/AlGaN nanowire heterostructures. Nano Lett, 2014, 14, 5118 doi: 10.1021/nl501845m[687] Miller D A B, Chemla D S, Damen T C, et al. Band-edge electroabsorption in quantum well structures: The quantum-confined Stark effect. Phys Rev Lett, 1984, 53, 2173 doi: 10.1103/PhysRevLett.53.2173[688] Carnevale S D, Kent T F, Phillips P J, et al. Polarization-induced pn diodes in wide-bandgap nanowires with ultraviolet electroluminescence. Nano Lett, 2012, 12, 915 doi: 10.1021/nl203982p[689] Jena D, Heikman S, Green D, et al. Realization of wide electron slabs by polarization bulk doping in graded III–V nitride semiconductor alloys. Appl Phys Lett, 2002, 81, 4395 doi: 10.1063/1.1526161[690] Green D S, Haus E, Wu F, et al. Polarity control during molecular beam epitaxy growth of Mg-doped GaN. J Vac Sci Technol B, 2003, 21, 1804 doi: 10.1116/1.1589511[691] Kuo Y K, Shih Y H, Tsai M C, et al. Improvement in electron overflow of near-ultraviolet InGaN LEDs by specific design on last barrier. IEEE Photonics Technol Lett, 2011, 23, 1630 doi: 10.1109/LPT.2011.2165838[692] Tangi M, Mishra P, Janjua B, et al. Bandgap measurements and the peculiar splitting of E2H phonon modes of InxAl1– xN nanowires grown by plasma assisted molecular beam epitaxy. J Appl Phys, 2016, 120, 045701 doi: 10.1063/1.4959260[693] Choi S, Wu F, Shivaraman R, et al. Observation of columnar microstructure in lattice-matched InAlN/GaN grown by plasma assisted molecular beam epitaxy. Appl Phys Lett, 2012, 100, 232102 doi: 10.1063/1.4725482[694] Zhang Z H, Tan S T, Ju Z, et al. On the effect of step-doped quantum barriers in InGaN/GaN light emitting diodes. J Disp Technol, 2013, 9, 226 doi: 10.1109/JDT.2012.2204858[695] Kneissl M, Kolbe T, Chua C, et al. Advances in group III-nitride-based deep UV light-emitting diode technology. Semicond Sci Technol, 2010, 26, 014036 doi: 10.1088/0268-1242/26/1/014036[696] Shatalov M, Sun W, Jain R, et al. High power AlGaN ultraviolet light emitters. Semicond Sci Technol, 2014, 29, 084007 doi: 10.1088/0268-1242/29/8/084007[697] Katsuragawa M, Sota S, Komori M, et al. Thermal ionization energy of Si and Mg in AlGaN. J Cryst Growth, 1998, 189, 528 doi: 10.1016/S0022-0248(98)00345-5[698] Li L, Miyachi Y, Miyoshi M, et al. Enhanced emission efficiency of deep ultraviolet light-emitting AlGaN multiple quantum wells grown on an n-AlGaN underlying layer. IEEE Photonics J, 2016, 8, 1601710 doi: 10.1109/jphot.2016.2601439[699] Zhang Z H, Zhang Y, Bi W, et al. A charge inverter for III-nitride light-emitting diodes. Appl Phys Lett, 2016, 108, 133502 doi: 10.1063/1.4945257[700] Ho J K, Jong C S, Chiu C C, et al. Low-resistance ohmic contacts to p-type GaN. Appl Phys Lett, 1999, 74, 1275 doi: 10.1063/1.123546[701] Chae S W, Kim K C, Kim D H, et al. Highly transparent and low-resistant ZnNi/indium tin oxide Ohmic contact on p-type GaN. Appl Phys Lett, 2007, 90, 181101 doi: 10.1063/1.2731672[702] Jang H W, Lee J L. Transparent Ohmic contacts of oxidized Ru and Ir on p-type GaN. J Appl Phys, 2003, 93, 5416 doi: 10.1063/1.1565494[703] Schubert E F, Grieshaber W, Goepfert I D. Enhancement of deep acceptor activation in semiconductors by superlattice doping. Appl Phys Lett, 1996, 69, 3737 doi: 10.1063/1.117206[704] Neugebauer S, Hoffmann M, Witte H, et al. All metalorganic chemical vapor phase epitaxy of p/n-GaN tunnel junction for blue light emitting diode applications. Appl Phys Lett, 2017, 110, 102104 doi: 10.1063/1.4978268[705] Zhang Y, Krishnamoorthy S, Akyol F, et al. Reflective metal/semiconductor tunnel junctions for hole injection in AlGaN UV LEDs. Appl Phys Lett, 2017, 111, 051104 doi: 10.1063/1.4997328[706] Krishnamoorthy S, Akyol F, Rajan S. InGaN/GaN tunnel junctions for hole injection in GaN light emitting diodes. Appl Phys Lett, 2014, 105, 141104 doi: 10.1063/1.4897342[707] Kuo Y K, Chang J Y, Chen F M, et al. Numerical investigation on the carrier transport characteristics of AlGaN deep-UV light-emitting diodes. IEEE J Quantum Electron, 2016, 52, 3300105 doi: 10.1109/jqe.2016.2535252[708] 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. Appl Phys Lett, 2013, 102, 231106 doi: 10.1063/1.4809947[709] Kim J K, Waldron E L, Li Y L, et al. P-type conductivity in bulk Al xGa1– xN and Al xGa1– xN/Al yGa1– yN superlattices with average Al mole fraction > 20%. Appl Phys Lett, 2004, 84, 3310 doi: 10.1063/1.1728322[710] Zhu T G, Denyszyn J C, Chowdhury U, et al. AlGaN-GaN UV light-emitting diodes grown on SiC by metal-organic chemical vapor deposition. IEEE J Sel Top Quantum Electron, 2002, 8, 298 doi: 10.1109/2944.999184[711] Zhang L, Ding K, Yan J C, et al. Three-dimensional hole gas induced by polarization in (0001)-oriented metal-face III-nitride structure. Appl Phys Lett, 2010, 97, 062103 doi: 10.1063/1.3478556[712] Zhang Z H, Li L, Zhang Y, et al. On the electric-field reservoir for III-nitride based deep ultraviolet light-emitting diodes. Opt Express, 2017, 25, 16550 doi: 10.1364/OE.25.016550[713] Jeon S R, Song Y H, Jang H J, et al. Lateral current spreading in GaN-based light-emitting diodes utilizing tunnel contact junctions. Appl Phys Lett, 2001, 78, 3265 doi: 10.1063/1.1374483[714] Mehnke F, Kuhn C, Guttmann M, et al. Efficient charge carrier injection into sub-250 nm AlGaN multiple quantum well light emitting diodes. Appl Phys Lett, 2014, 105, 051113 doi: 10.1063/1.4892883[715] Tsai C L, Liu H H, Chen J W, et al. Improving the light output power of DUV-LED by introducing an intrinsic last quantum barrier interlayer on the high-quality AlN template. Solid-State Electron, 2017, 138, 84 doi: 10.1016/j.sse.2017.09.009[716] Zhang Z H, Huang Chen S W, Zhang Y, et al. Hole transport manipulation to improve the hole injection for deep ultraviolet light-emitting diodes. ACS Photonics, 2017, 4, 1846 doi: 10.1021/acsphotonics.7b00443[717] Tsai M C, Yen S H, Kuo Y K. Deep-ultraviolet light-emitting diodes with gradually increased barrier thicknesses from n-layers to p-layers. Appl Phys Lett, 2011, 98, 111114 doi: 10.1063/1.3567786[718] Kolbe T, Sembdner T, Knauer A, et al. (In)AlGaN deep ultraviolet light emitting diodes with optimized quantum well width. Phys Status Solidi A, 2010, 207, 2198 doi: 10.1002/pssa.201026046[719] Norimichi N, Hirayama H, Yatabe T, et al. 222 nm single-peaked deep-UV LED with thin AlGaN quantum well layers. Phys Status Solidi C, 2009, 6, S459 doi: 10.1002/pssc.200880923[720] Hirayama H, Noguchi N, Yatabe T, et al. 227 nm AlGaN light-emitting diode with 0.15 mW output power realized using a thin quantum well and AlN buffer with reduced threading dislocation density. Appl Phys Express, 2008, 1, 051101 doi: 10.1143/APEX.1.051101[721] Hirayama H, Yatabe T, Noguchi N, et al. 231–261 nm AlGaN deep-ultraviolet light-emitting diodes fabricated on AlN multilayer buffers grown by ammonia pulse-flow method on sapphire. Appl Phys Lett, 2007, 91, 071901 doi: 10.1063/1.2770662[722] Xiu X, Zhang L, Li Y, Xiong Z, et al. Application of halide vapor phase epitaxy for the growth of ultra-wide band gap Ga2O3. J Semicond, 2019, 40, 011805 doi: 10.1088/1674-4926/40/1/011805[723] Pratiyush A S, Krishnamoorthy S, Muralidharan R, et al. Advances in Ga2O3 solar-blind UV photodetectors. In: Gallium Oxide. Elsevier, 2019, 369[724] Sedhain A, Lin J Y, Jiang H X. Nature of optical transitions involving cation vacancies and complexes in AlN and AlGaN. Appl Phys Lett, 2012, 100, 221107 doi: 10.1063/1.4723693[725] Bickermann M, Epelbaum B M, Filip O, et al. Deep-UV transparent bulk single-crystalline AlN substrates. Phys Status Solidi C, 2010, 7, 1743 doi: 10.1002/pssc.200983422[726] Bondokov R T, Mueller S G, Morgan K E, et al. Large-area AlN substrates for electronic applications: An industrial perspective. J Cryst Growth, 2008, 310, 4020 doi: 10.1016/j.jcrysgro.2008.06.032[727] Bickermann M, Epelbaum B M, Winnacker A. PVT growth of bulk AlN crystals with low oxygen contamination. Phys Status Solidi C, 1993, 1993 doi: 10.1002/pssc.200303280[728] Slack G A, Schowalter L J, Morelli D, et al. Some effects of oxygen impurities on AlN and GaN. J Cryst Growth, 2002, 246, 287 doi: 10.1016/S0022-0248(02)01753-0[729] 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. Appl Phys Lett, 2019, 114, 102101 doi: 10.1063/1.5087543[730] Chu C, Tian K, Zhang Y, et al. Progress in external quantum efficiency for III-nitride based deep ultraviolet light-emitting diodes. Phys Status Solidi A, 2019, 216, 1800815 doi: 10.1002/pssa.201800815[731] Bryan I, Bryan Z, Washiyama S, et al. Doping and compensation in Al-rich AlGaN grown on single crystal AlN and sapphire by MOCVD. Appl Phys Lett, 2018, 112, 062102 doi: 10.1063/1.5011984[732] Kirste R, Mita S, Guo Q, et al. Recent breakthroughs in AlGaNbased UV light emitters. IEEE Research and Applications of Photonics In Defense Conference (RAPID), 2018, 18196129[733] 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 Cryst Growth, 2016, 438, 81 doi: 10.1016/j.jcrysgro.2015.12.022[734] Hartmann C, Wollweber J, Dittmar A, et al. Preparation of bulk AlN seeds by spontaneous nucleation of freestanding crystals. Jpn J Appl Phys, 2013, 52, 08JA06 doi: 10.7567/JJAP.52.08JA06[735] Sumathi R R. Bulk AlN single crystal growth on foreign substrate and preparation of free-standing native seeds. Cryst Eng Comm, 2013, 15, 2232 doi: 10.1039/C2CE26599K[736] Mokhov E, Izmaylova I, Kazarova O, et al. Specific features of sublimation growth of bulk AlN crystals on SiC wafers. Phys Status Solidi C, 2013, 10, 445 doi: 10.1002/pssc.201200638[737] Park S H, Shim J I. Carrier density dependence of polarization switching characteristics of light emission in deep-ultraviolet AlGaN/AlN quantum well structures. Appl Phys Lett, 2013, 102, 221109 doi: 10.1063/1.4809759[738] Dalmau R, Moody B, Xie J, et al. Characterization of dislocation arrays in AlN single crystals grown by PVT. Phys Status Solidi A, 2011, 208, 1545 doi: 10.1002/pssa.201000957[739] Herro Z, Zhuang D, Schlesser R, et al. Growth of AlN single crystalline boules. J Cryst Growth, 2010, 312, 2519 doi: 10.1016/j.jcrysgro.2010.04.005[740] Kinoshita T, Obata T, Nagashima T, et al. Performance and reliability of deep-ultraviolet light-emitting diodes fabricated on AlN substrates prepared by hydride vapor phase epitaxy. Appl Phys Express, 2013, 6, 092103 doi: 10.7567/APEX.6.092103[741] Kinoshita T, Hironaka K, Obata T, et al. Deep-ultraviolet light-emitting diodes fabricated on AlN substrates prepared by hydride vapor phase epitaxy. Appl Phys Express, 2012, 5, 122101 doi: 10.1143/APEX.5.122101[742] Grandusky J R, Chen J, Gibb S R, et al. 270 nm pseudomorphic ultraviolet light-emitting diodes with over 60 mW continuous wave output power. Appl Phys Express, 2013, 6, 032101 doi: 10.7567/APEX.6.032101[743] An Y, Sun Y, Zhang M, et al. Tuning the electronic structures and transport properties of zigzag blue phosphorene nanoribbons. IEEE Trans Electron Devices, 2018, 65, 4646 doi: 10.1109/TED.2018.2863658[744] Liu H, Neal A T, Zhu Z, Luo Z, et al. Phosphorene: An unexplored 2D semiconductor with a high hole mobility. ACS Nano, 2014, 8, 4033 doi: 10.1021/nn501226z[745] Zhang M, An Y, Sun Y, et al. The electronic transport properties of zigzag phosphorene-like MX (M = Ge/Sn, X = S/Se) nanostructures. Phys Chem Chem Phys, 2017, 19, 17210 doi: 10.1039/C7CP02201H[746] Li F, Liu X, Wang Y, et al. Germanium monosulfide monolayer: a novel two-dimensional semiconductor with a high carrier mobility. J Mater Chem C, 2016, 4, 2155 doi: 10.1039/C6TC00454G[747] Dagan R, Vaknin Y, Henning A, et al. Two-dimensional charge carrier distribution in MoS2 monolayer and multilayers. Appl Phys Lett, 2019, 114, 101602 doi: 10.1063/1.5078711[748] Zhou X, Hu X, Yu J, et al. 2D layered material-based van der Waals heterostructures for optoelectronics. Adv Funct Mater, 2018, 28, 1706587 doi: 10.1002/adfm.v28.14[749] Nayeri M, Fathipour M. A numerical analysis of electronic and optical properties of the zigzag MoS2 nanoribbon under uniaxial strain. IEEE Trans Electron Devices, 2018, 65, 1988 doi: 10.1109/TED.2018.2810604[750] Fan Z Q, Jiang X W, Luo J W, et al. In-plane Schottky-barrier field-effect transistors based on 1T/2H heterojunctions of transition-metal dichalcogenides. Phys Rev B, 2017, 96, 165402 doi: 10.1103/PhysRevB.96.165402[751] An Y, Zhang M, Wu D, et al. The electronic transport properties of transition-metal dichalcogenide lateral heterojunctions. J Mater Chem C, 2016, 4, 10962 doi: 10.1039/C6TC04327E[752] Cheng R, Li D, Zhou H, et al. Electroluminescence and photocurrent generation from atomically sharp WSe2/MoS2 heterojunction p-n diodes. Nano Lett, 2014, 14, 5590 doi: 10.1021/nl502075n[753] Zhao J, Cheng K, Han N, et al. Growth control, interface behavior, band alignment, and potential device applications of 2D lateral heterostructures. Wiley Interdiscip Rev Comput Mol Sci, 2018, 8, e1353 doi: 10.1002/wcms.2018.8.issue-2[754] Koppens F H L, Mueller T, Avouris P, et al . Photodetectors based on graphene, other two-dimensional materials and hybrid systems. Nat Nanotechnol, 2014, 9, 780 doi: 10.1038/nnano.2014.215[755] Zhu X, Lei S, Tsai S H, et al. A study of vertical transport through graphene toward control of quantum tunneling. Nano Lett, 2018, 18, 682 doi: 10.1021/acs.nanolett.7b03221[756] Asres G A, Järvinen T, Lorite G S,et al. High photoresponse of individual WS2 nanowire-nanoflake hybrid materials. Appl Phys Lett, 2018, 112, 233103 doi: 10.1063/1.5030490[757] Chu D, Lee Y H, Kim E K. Selective control of electron and hole tunneling in 2D assembly. Sci Adv, 2017, 3, e1602726 doi: 10.1126/sciadv.1602726[758] Yamaguchi T, Moriya R, Inoue Y, et al. Tunneling transport in a few monolayer-thick WS2/graphene heterojunction. Appl Phys Lett, 2014, 105, 223109 doi: 10.1063/1.4903190[759] Xia F, Wang H, Xiao D, et al. Two-dimensional material nanophotonics. Nat Photonics, 2014, 8, 899 doi: 10.1038/nphoton.2014.271[760] Kim S, Oh S, Kim J. Ultrahigh deep-UV sensitivity in graphene-gated β-Ga2O3 phototransistors. ACS Photonics, 2019, 6, 1026 doi: 10.1021/acsphotonics.9b00032[761] Schubert M, Mock A, Korlacki R, et al. Longitudinal phonon plasmon mode coupling in β-Ga2O3. Appl Phys Lett, 2019, 114, 102102 doi: 10.1063/1.5089145[762] Polyakov A Y, Smirnov N B, Shchemerov I V, et al. Electrical properties of bulk semi-insulating β-Ga2O3(Fe). Appl Phys Lett, 2018, 113, 142102 doi: 10.1063/1.5051986[763] Hu Z, Nomoto K, Li W, et al. Breakdown mechanism in 1 kA/cm2 and 960 V E-mode β-Ga2O3 vertical transistors. Appl Phys Lett, 2018, 113, 122103 doi: 10.1063/1.5038105[764] Joishi C, Xia Z, McGlone J, et al. Effect of buffer iron doping on delta-doped β-Ga2O3 metal semiconductor field effect transistors. Appl Phys Lett, 2018, 113, 123501 doi: 10.1063/1.5039502[765] Neal A T, Mou S, Rafique S, et al. Donors and deep acceptors in β-Ga2O3. Appl Phys Lett, 2018, 113, 062101 doi: 10.1063/1.5034474[766] Wong M H, Lin C H, Kuramata A, et al. Acceptor doping of β-Ga2O3 by Mg and N ion implantations. Appl Phys Lett, 2018, 113, 102103 doi: 10.1063/1.5050040[767] Yang J, Ren F, Tadjer M, et al. Ga2O3 Schottky rectifiers with 1 ampere forward current, 650 V reverse breakdown and 26.5 MW·cm-2 figure-of-merit. AIP Adv, 2018, 8, 055026 doi: 10.1063/1.5034444[768] Lee S U, Jeong J. Short time helium annealing for solution-processed amorphous indium-gallium-zinc-oxide thin film transistors. AIP Adv, 2018, 8, 085206 doi: 10.1063/1.5040019[769] Polyakov A Y, Smirnov N B, Shchemerov I V, et al. Defects responsible for charge carrier removal and correlation with deep level introduction in irradiated β-Ga2O3. Appl Phys Lett, 2018, 113, 092102 doi: 10.1063/1.5049130[770] Gibbon J T, Jones L, Roberts J W, et al. Band alignments at Ga2O3 heterojunction interfaces with Si and Ge. AIP Adv, 2018, 8, 065011 doi: 10.1063/1.5034459[771] Zhang S, Lian X, Ma Y, et al. Growth and characterization of 2-inch high quality β-Ga2O3 single crystals grown by EFG method. J Semicond, 2018, 39, 083003 doi: 10.1088/1674-4926/39/8/083003[772] Polyakov A Y, Smirnov N B, Shchemerov I V, et al. Compensation and persistent photocapacitance in homoepitaxial Sn-doped β-Ga2O3. J Appl Phys, 2018, 123, 115702 doi: 10.1063/1.5025916[773] Zhang K, Feng Q, Huang L, et al. (InxGa1– x)2O3 photodetectors fabricated on sapphire at different temperatures by PLD. IEEE Photon J, 2018, 10, 6802508 doi: 10.1109/JPHOT.2018.2841968[774] Feng Q, Hu Z, Feng Z, et al. Research on the growth of β-(AlGa)2O3 film and the analysis of electrical characteristics of Ni/Au Schottky contact using Tung’s model. Superlattices Microstruct, 2018, 120, 441-447 doi: 10.1016/j.spmi.2018.05.032[775] Feng Q, Feng Z, Hu Z, et al. Temperature dependent electrical properties of pulse laser deposited Au/Ni/β-(AlGa)2O3 Schottky diode. Appl Phys Lett, 2018, 112, 072103 doi: 10.1063/1.5019310[776] Zhang Y, Joishi C, Xia Z, et al. Demonstration of β-(AlxGa1– x)2O3/ Ga2O3 double heterostructure field effect transistors. Appl Phys Lett, 2018, 112, 233503 doi: 10.1063/1.5037095[777] Zhang Y, Neal A, Xia Z, et al. Demonstration of high mobility and quantum transport in modulationdoped β-(AlxGa1– x)2O3/Ga2O3 heterostructures. Appl Phys Lett, 2018, 112, 173502 doi: 10.1063/1.5025704[778] Chen X, Xu Y, Zhou D, et al. Solar-blind photodetector with high avalanche gains and bias-tunable detecting functionality based on metastable phase α-Ga2O3/ZnO isotype heterostructures. ACS Appl Mater Interfaces, 2017, 9, 36997-37005 doi: 10.1021/acsami.7b09812[779] Oshima T, Okuno T, Fujita S. Ga2O3 thin film growth on c-plane sapphire substrates by molecular beam epitaxy for deep-ultraviolet photodetectors. Jpn J Appl Phys, 2007, 46, 7217 doi: 10.1143/JJAP.46.7217[780] Qian L X, Wu Z H, Zhang Y Y, et al. Ultrahigh-responsivity, rapid-recovery, solar-blind photodetector based on highly nonstoichiometric amorphous gallium oxide. ACS Photonics, 2017, 4, 2203 doi: 10.1021/acsphotonics.7b00359[781] Orita M, Ohta H, Hirano M, et al. Deep-ultraviolet transparent conductive β-Ga2O3 thin films. Appl Phys Lett, 2000, 77, 4166 doi: 10.1063/1.1330559[782] Pratiyush A S, Krishnamoorthy S, Solanke S V, et al. High responsivity in molecular beam epitaxy grown β-Ga2O3 metal semiconductor metal solar blind deep-UV photodetector. Appl Phys Lett, 2017, 110, 221107 doi: 10.1063/1.4984904[783] Guo D, Wu Z, Li P, et al. Fabrication of β-Ga2O3 thin films and solar-blind photodetectors by laser MBE technology. Opt Mater Express, 2014, 4, 1067 doi: 10.1364/OME.4.001067[784] Moudgil A, Dhyani V, Das S. High speed efficient ultraviolet photodetector based on 500 nm width multiple WO3 nanowires. Appl Phys Lett, 2018, 113, 101101 doi: 10.1063/1.5045249[785] Khan F, Khan W, Kim J H, et al. Oxygen desorption kinetics of ZnO nanorod-gated AlGaN/GaN HEMT-based UV photodetectors. AIP Adv, 2018, 8, 075225 doi: 10.1063/1.5040295 -
Proportional views
