Gallium nitride

Gallium nitride
Names
IUPAC name
Gallium nitride
Other names
gallium(III) nitride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.042.830 Edit this at Wikidata
UNII
  • InChI=1S/Ga.N checkY
    Key: JMASRVWKEDWRBT-UHFFFAOYSA-N checkY
  • InChI=1/Ga.N/rGaN/c1-2
    Key: JMASRVWKEDWRBT-MDMVGGKAAI
  • [Ga]#N
  • [Ga+3].[N-3]
Properties
GaN
Molar mass 83.730 g/mol[1]
Appearance yellow powder
Density 6.1 g/cm3[1]
Melting point > 1600 °C[1][2]
Insoluble[3]
Band gap 3.4 eV (300 K, direct)
Electron mobility 1500 cm2/(V·s) (300 K)[4]
Thermal conductivity 1.3 W/(cm·K) (300 K)[5]
2.429
Structure
Wurtzite
C6v4-P63mc
a = 3.186 Å, c = 5.186 Å[6]
Tetrahedral
Thermochemistry
−110.2 kJ/mol[7]
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H317
P261, P272, P280, P302+P352, P321, P333+P313, P501
NFPA 704 (fire diamond)
Flash point Non-flammable
Safety data sheet (SDS) Sigma-Aldrich Co., Gallium nitride. Retrieved on 18 February 2024.
Related compounds
Other anions
Gallium phosphide
Gallium arsenide
Gallium antimonide
Other cations
Boron nitride
Aluminium nitride
Indium nitride
Related compounds
Aluminium gallium arsenide
Indium gallium arsenide
Gallium arsenide phosphide
Aluminium gallium nitride
Indium gallium nitride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Gallium nitride (GaN) is a binary III/V direct bandgap semiconductor commonly used in blue light-emitting diodes since the 1990s. The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it special properties for applications in optoelectronic,[9][10][11] high-power and high-frequency devices. For example, GaN is the substrate that makes violet (405 nm) laser diodes possible, without requiring nonlinear optical frequency doubling.

Its sensitivity to ionizing radiation is low (like other group III nitrides), making it a suitable material for solar cell arrays for satellites. Military and space applications could also benefit as devices have shown stability in high radiation environments.[12]

Because GaN transistors can operate at much higher temperatures and work at much higher voltages than gallium arsenide (GaAs) transistors, they make ideal power amplifiers at microwave frequencies. In addition, GaN offers promising characteristics for THz devices.[13] Due to high power density and voltage breakdown limits GaN is also emerging as a promising candidate for 5G cellular base station applications. Since the early 2020s, GaN power transistors have come into increasing use in power supplies in electronic equipment, converting AC mains electricity to low-voltage DC.

Physical properties

GaN crystal

GaN is a very hard (Knoop hardness 14.21 GPa[14]: 4 ), mechanically stable wide-bandgap semiconductor material with high heat capacity and thermal conductivity.[15] In its pure form it resists cracking and can be deposited in thin film on sapphire or silicon carbide, despite the mismatch in their lattice constants.[15] GaN can be doped with silicon (Si) or with oxygen[16] to n-type and with magnesium (Mg) to p-type.[17][18] However, the Si and Mg atoms change the way the GaN crystals grow, introducing tensile stresses and making them brittle.[19] Gallium nitride compounds also tend to have a high dislocation density, on the order of 108 to 1010 defects per square centimeter.[20]

The U.S. Army Research Laboratory (ARL) provided the first measurement of the high field electron velocity in GaN in 1999.[21] Scientists at ARL experimentally obtained a peak steady-state velocity of 1.9×107 cm/s, with a transit time of 2.5 picoseconds, attained at an electric field of 225 kV/cm. With this information, the electron mobility was calculated, thus providing data for the design of GaN devices.

Developments

One of the earliest syntheses of gallium nitride was at the George Herbert Jones Laboratory in 1932.[22]

An early synthesis of gallium nitride was by Robert Juza and Harry Hahn in 1938.[23]

GaN with a high crystalline quality can be obtained by depositing a buffer layer at low temperatures.[24] Such high-quality GaN led to the discovery of p-type GaN,[17] p–n junction blue/UV-LEDs[17] and room-temperature stimulated emission[25] (essential for laser action).[26] This has led to the commercialization of high-performance blue LEDs and long-lifetime violet laser diodes, and to the development of nitride-based devices such as UV detectors and high-speed field-effect transistors.[citation needed]

LEDs

High-brightness GaN light-emitting diodes (LEDs) completed the range of primary colors, and made possible applications such as daylight-visible full-color LED displays, white LEDs and blue laser devices. The first GaN-based high-brightness LEDs used a thin film of GaN deposited via metalorganic vapour-phase epitaxy (MOVPE) on sapphire. Other substrates used are zinc oxide, with lattice constant mismatch of only 2% and silicon carbide (SiC).[27] Group III nitride semiconductors are, in general, recognized as one of the most promising semiconductor families for fabricating optical devices in the visible short-wavelength and UV region.[citation needed]

GaN transistors and power ICs

The very high breakdown voltages,[28] high electron mobility, and high saturation velocity of GaN has made it an ideal candidate for high-power and high-temperature microwave applications, as evidenced by its high Johnson's figure of merit. Potential markets for high-power/high-frequency devices based on GaN include microwave radio-frequency power amplifiers (e.g., those used in high-speed wireless data transmission) and high-voltage switching devices for power grids. A potential mass-market application for GaN-based RF transistors is as the microwave source for microwave ovens, replacing the magnetrons currently used. The large band gap means that the performance of GaN transistors is maintained up to higher temperatures (~400 °C[29]) than silicon transistors (~150 °C[29]) because it lessens the effects of thermal generation of charge carriers that are inherent to any semiconductor. The first gallium nitride metal semiconductor field-effect transistors (GaN MESFET) were experimentally demonstrated in 1993[30] and they are being actively developed.

In 2010, the first enhancement-mode GaN transistors became generally available.[31] Only n-channel transistors were available.[31] These devices were designed to replace power MOSFETs in applications where switching speed or power conversion efficiency is critical. These transistors are built by growing a thin layer of GaN on top of a standard silicon wafer, often referred to as GaN-on-Si by manufacturers.[32] This allows the FETs to maintain costs similar to silicon power MOSFETs but with the superior electrical performance of GaN. Another seemingly viable solution for realizing enhancement-mode GaN-channel HFETs is to employ a lattice-matched quaternary AlInGaN layer of acceptably low spontaneous polarization mismatch to GaN.[33]

GaN power ICs monolithically integrate a GaN FET, GaN-based drive circuitry and circuit protection into a single surface-mount device.[34] [35] Integration means that the gate-drive loop has essentially zero impedance, which further improves efficiency by virtually eliminating FET turn-off losses. Academic studies into creating low-voltage GaN power ICs began at the Hong Kong University of Science and Technology (HKUST) and the first devices were demonstrated in 2015. Commercial GaN power IC production began in 2018.

CMOS logic

In 2016 the first GaN CMOS logic using PMOS and NMOS transistors was reported with gate lengths of 0.5 μm (gate widths of the PMOS and NMOS transistors were 500 μm and 50 μm, respectively).[36]

Applications

LEDs and lasers

GaN-based violet laser diodes are used to read Blu-ray Discs. The mixture of GaN with In (InGaN) or Al (AlGaN) with a band gap dependent on the ratio of In or Al to GaN allows the manufacture of light-emitting diodes (LEDs) with colors that can go from red to ultra-violet.[27]

Transistors and power ICs

GaN high-electron-mobility transistors (manufactured by Ferdinand-Braun-Institut)

GaN transistors are suitable for high frequency, high voltage, high temperature and high-efficiency applications.[37][38] GaN is efficient at transferring current, and this ultimately means that less energy is lost to heat. [39]

GaN high-electron-mobility transistors (HEMT) have been offered commercially since 2006, and have found immediate use in various wireless infrastructure applications due to their high efficiency and high voltage operation. A second generation of devices with shorter gate lengths will address higher-frequency telecom and aerospace applications.[40]

GaN-based metal–oxide–semiconductor field-effect transistors (MOSFET) and metal–semiconductor field-effect transistor (MESFET) transistors also offer advantages including lower loss in high power electronics, especially in automotive and electric car applications.[41] Since 2008 these can be formed on a silicon substrate.[41] High-voltage (800 V) Schottky barrier diodes (SBDs) have also been made.[41]

The higher efficiency and high power density of integrated GaN power ICs allows them to reduce the size, weight and component count of applications including mobile and laptop chargers, consumer electronics, computing equipment and electric vehicles.

GaN-based electronics (not pure GaN) have the potential to drastically cut energy consumption, not only in consumer applications but even for power transmission utilities.

Unlike silicon transistors that switch off due to power surges,[clarification needed] GaN transistors are typically depletion mode devices (i.e. on / resistive when the gate-source voltage is zero). Several methods have been proposed to reach normally-off (or E-mode) operation, which is necessary for use in power electronics:[42][43]

  • the implantation of fluorine ions under the gate (the negative charge of the F-ions favors the depletion of the channel)
  • the use of a MIS-type gate stack, with recess of the AlGaN
  • the integration of a cascaded pair constituted by a normally-on GaN transistor and a low voltage silicon MOSFET
  • the use of a p-type layer on top of the AlGaN/GaN heterojunction

Radars

GaN technology is also utilized in military electronics such as active electronically scanned array radars.[44]

Thales Group introduced the Ground Master 400 radar in 2010 utilizing GaN technology. In 2021 Thales put in operation more than 50,000 GaN Transmitters on radar systems.[45]

The U.S. Army funded Lockheed Martin to incorporate GaN active-device technology into the AN/TPQ-53 radar system to replace two medium-range radar systems, the AN/TPQ-36 and the AN/TPQ-37.[46][47] The AN/TPQ-53 radar system was designed to detect, classify, track, and locate enemy indirect fire systems, as well as unmanned aerial systems.[48] The AN/TPQ-53 radar system provided enhanced performance, greater mobility, increased reliability and supportability, lower life-cycle cost, and reduced crew size compared to the AN/TPQ-36 and the AN/TPQ-37 systems.[46]

Lockheed Martin fielded other tactical operational radars with GaN technology in 2018, including TPS-77 Multi Role Radar System deployed to Latvia and Romania.[49] In 2019, Lockheed Martin's partner ELTA Systems Limited, developed a GaN-based ELM-2084 Multi Mission Radar that was able to detect and track air craft and ballistic targets, while providing fire control guidance for missile interception or air defense artillery.

On April 8, 2020, Saab flight tested its new GaN designed AESA X-band radar in a JAS-39 Gripen fighter.[50] Saab already offers products with GaN based radars, like the Giraffe radar, Erieye, GlobalEye, and Arexis EW.[51][52][53][54] Saab also delivers major subsystems, assemblies and software for the AN/TPS-80 (G/ATOR)[55]

India's Defence Research and Development Organisation is developing Virupaakhsha radar for Sukhoi Su-30MKI based on GaN technology. The radar is a further development of Uttam AESA Radar for use on HAL Tejas which employs GaAs technology. [56][57][58]

Nanoscale

GaN nanotubes and nanowires are proposed for applications in nanoscale electronics, optoelectronics and biochemical-sensing applications.[59][60]

Spintronics potential

When doped with a suitable transition metal such as manganese, GaN is a promising spintronics material (magnetic semiconductors).[27]

Synthesis

Bulk substrates

GaN crystals can be grown from a molten Na/Ga melt held under 100 atmospheres of pressure of N2 at 750 °C. As Ga will not react with N2 below 1000 °C, the powder must be made from something more reactive, usually in one of the following ways:

2 Ga + 2 NH3 → 2 GaN + 3 H2[61]
Ga2O3 + 2 NH3 → 2 GaN + 3 H2O[62]

Gallium nitride can also be synthesized by injecting ammonia gas into molten gallium at 900–980 °C at normal atmospheric pressure.[63]

Metal-organic vapour phase epitaxy

Blue, white and ultraviolet LEDs are grown on industrial scale by MOVPE.[64][65] The precursors are ammonia with either trimethylgallium or triethylgallium, the carrier gas being nitrogen or hydrogen. Growth temperature ranges between 800 and 1100 °C. Introduction of trimethylaluminium and/or trimethylindium is necessary for growing quantum wells and other kinds of heterostructures.

Molecular beam epitaxy

Commercially, GaN crystals can be grown using molecular beam epitaxy or metalorganic vapour phase epitaxy. This process can be further modified to reduce dislocation densities. First, an ion beam is applied to the growth surface in order to create nanoscale roughness. Then, the surface is polished. This process takes place in a vacuum. Polishing methods typically employ a liquid electrolyte and UV irradiation to enable mechanical removal of a thin oxide layer from the wafer. More recent methods have been developed that utilize solid-state polymer electrolytes that are solvent-free and require no radiation before polishing.[66]

Safety

GaN dust is an irritant to skin, eyes and lungs. The environment, health and safety aspects of gallium nitride sources (such as trimethylgallium and ammonia) and industrial hygiene monitoring studies of MOVPE sources have been reported in a 2004 review.[67]

Bulk GaN is non-toxic and biocompatible.[68] Therefore, it may be used in the electrodes and electronics of implants in living organisms.

See also

References

  1. ^ a b c Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.64. ISBN 1-4398-5511-0.
  2. ^ Harafuji, Kenji; Tsuchiya, Taku; Kawamura, Katsuyuki (2004). "Molecular dynamics simulation for evaluating melting point of wurtzite-type GaN crystal". Journal of Applied Physics. 96 (5): 2501. Bibcode:2004JAP....96.2501H. doi:10.1063/1.1772878.
  3. ^ Foster, Corey M.; Collazo, Ramon; Sitar, Zlatko; Ivanisevic, Albena (2013). "abstract NCSU study: Aqueous Stability of Ga- and N-Polar Gallium Nitride". Langmuir. 29 (1): 216–220. doi:10.1021/la304039n. PMID 23227805.
  4. ^ Johan Strydom; Michael de Rooij; David Reusch; Alex Lidow (2019). GaN Transistors for efficient power conversion (3 ed.). California, USA: Wiley. p. 3. ISBN 978-1-119-59442-0.
  5. ^ Mion, Christian (2005). "Investigation of the Thermal Properties of Gallium Nitride Using the Three Omega Technique", Thesis, North Carolina State University.
  6. ^ Bougrov V., Levinshtein M.E., Rumyantsev S.L., Zubrilov A., in Properties of Advanced Semiconductor Materials GaN, AlN, InN, BN, SiC, SiGe. Eds. Levinshtein M.E., Rumyantsev S.L., Shur M.S., John Wiley & Sons, Inc., New York, 2001, 1–30
  7. ^ Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 5.12. ISBN 1-4398-5511-0.
  8. ^ "Safety Data Sheet". fishersci.com. Thermo Fisher Science. 2020. Retrieved 18 February 2024.
  9. ^ Czelej, K. (2024). "Atomistic Origins of Various Luminescent Centers and n-Type Conductivity in GaN: Exploring the Point Defects Induced by Cr, Mn, and O through an Ab Initio Thermodynamic Approach". Chemistry of Materials. 36 (13): 6392–6409. doi:10.1021/acs.chemmater.4c00178.
  10. ^ Di Carlo, A. (2001). "Tuning Optical Properties of GaN-Based Nanostructures by Charge Screening". Physica Status Solidi A. 183 (1): 81–85. Bibcode:2001PSSAR.183...81D. doi:10.1002/1521-396X(200101)183:1<81::AID-PSSA81>3.0.CO;2-N.
  11. ^ Arakawa, Y. (2002). "Progress in GaN-based quantum dots for optoelectronics applications". IEEE Journal of Selected Topics in Quantum Electronics. 8 (4): 823–832. Bibcode:2002IJSTQ...8..823A. doi:10.1109/JSTQE.2002.801675.
  12. ^ Lidow, Alexander; Witcher, J. Brandon; Smalley, Ken (March 2011). "Enhancement Mode Gallium Nitride (eGaN) FET Characteristics under Long Term Stress" (PDF). GOMAC Tech Conference.
  13. ^ Ahi, Kiarash (September 2017). "Review of GaN-based devices for terahertz operation". Optical Engineering. 56 (9): 090901. Bibcode:2017OptEn..56i0901A. doi:10.1117/1.OE.56.9.090901 – via SPIE.
  14. ^ "Gallium Nitride as an Electromechanical Material. R-Z. IEEE 2014" (PDF).
  15. ^ a b Akasaki, I.; Amano, H. (1997). "Crystal Growth and Conductivity Control of Group III Nitride Semiconductors and Their Application to Short Wavelength Light Emitters". Japanese Journal of Applied Physics. 36 (9A): 5393. Bibcode:1997JaJAP..36.5393A. doi:10.1143/JJAP.36.5393.
  16. ^ Wetzel, C.; Suski, T.; Ager, J.W. III; Fischer, S.; Meyer, B.K.; Grzegory, I.; Porowski, S. (1996) Strongly localized donor level in oxygen doped gallium nitride, International conference on physics of semiconductors, Berlin (Germany), 21–26 July 1996.
  17. ^ a b c Amano, H.; Kito, M.; Hiramatsu, K.; Akasaki, I. (1989). "P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron Beam Irradiation (LEEBI)". Japanese Journal of Applied Physics. 28 (12): L2112. Bibcode:1989JaJAP..28L2112A. doi:10.1143/JJAP.28.L2112.
  18. ^ "Discovery in gallium nitride a key enabler of energy efficient electronics". Cornell Chronicle. Retrieved 20 October 2022.
  19. ^ Terao, S.; Iwaya, M.; Nakamura, R.; Kamiyama, S.; Amano, H.; Akasaki, I. (2001). "Fracture of AlxGa1−xN/GaN Heterostructure – Compositional and Impurity Dependence –". Japanese Journal of Applied Physics. 40 (3A): L195. Bibcode:2001JaJAP..40..195T. doi:10.1143/JJAP.40.L195. S2CID 122191162.
  20. ^ Preuss, Paul (11 August 2000). Blue Diode Research Hastens Day of Large-Scale Solid-State Light Sources Archived 25 October 2010 at the Wayback Machine. Berkeley Lab., lbl.gov.
  21. ^ Wraback, M.; Shen, H.; Carrano, J.C.; Collins, C.J; Campbell, J.C.; Dupuis, R.D.; Schurman, M.J.; Ferguson, I.T. (2000). "Time-Resolved Electroabsorption Measurement of the electron velocity-field characteristic in GaN". Applied Physics Letters. 76 (9): 1155–1157. Bibcode:2000ApPhL..76.1155W. doi:10.1063/1.125968.
  22. ^ Ahmad, Majeed (23 May 2023). "A brief history of gallium nitride (GaN) semiconductors". EDN. Retrieved 31 August 2023.
  23. ^ Juza, Robert; Hahn, Harry (1938). "Über die Kristallstrukturen von Cu3N, GaN und InN Metallamide und Metallnitride". Zeitschrift für Anorganische und Allgemeine Chemie. 239 (3): 282–287. doi:10.1002/zaac.19382390307.
  24. ^ Amano, H.; Sawaki, N.; Akasaki, I.; Toyoda, Y. (1986). "Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer". Applied Physics Letters. 48 (5): 353. Bibcode:1986ApPhL..48..353A. doi:10.1063/1.96549. S2CID 59066765.
  25. ^ Amano, H.; Asahi, T.; Akasaki, I. (1990). "Stimulated Emission Near Ultraviolet at Room Temperature from a GaN Film Grown on Sapphire by MOVPE Using an AlN Buffer Layer". Japanese Journal of Applied Physics. 29 (2): L205. Bibcode:1990JaJAP..29L.205A. doi:10.1143/JJAP.29.L205. S2CID 120489784.
  26. ^ Akasaki, I.; Amano, H.; Sota, S.; Sakai, H.; Tanaka, T.; Koike, M. (1995). "Stimulated Emission by Current Injection from an AlGaN/GaN/GaInN Quantum Well Device". Japanese Journal of Applied Physics. 34 (11B): L1517. Bibcode:1995JaJAP..34L1517A. doi:10.7567/JJAP.34.L1517.
  27. ^ a b c Morkoç, H.; Strite, S.; Gao, G. B.; Lin, M. E.; Sverdlov, B.; Burns, M. (1994). "Large-band-gap SiC, III–V nitride, and II–VI ZnSe-based semiconductor device technologies". Journal of Applied Physics. 76 (3): 1363. Bibcode:1994JAP....76.1363M. doi:10.1063/1.358463.
  28. ^ Dora, Y.; Chakraborty, A.; McCarthy, L.; Keller, S.; Denbaars, S. P.; Mishra, U. K. (2006). "High Breakdown Voltage Achieved on AlGaN/GaN HEMTs with Integrated Slant Field Plates". IEEE Electron Device Letters. 27 (9): 713. Bibcode:2006IEDL...27..713D. doi:10.1109/LED.2006.881020. S2CID 38268864.
  29. ^ a b "Why GaN Systems". 29 November 2023.
  30. ^ Asif Khan, M.; Kuznia, J. N.; Bhattarai, A. R.; Olson, D. T. (1993). "Metal semiconductor field effect transistor based on single crystal GaN". Applied Physics Letters. 62 (15): 1786. Bibcode:1993ApPhL..62.1786A. doi:10.1063/1.109549.
  31. ^ a b Davis, Sam (March 2010). "Enhancement Mode GaN MOSFET Delivers Impressive Performance". Electronic Design. 36 (3).
  32. ^ "GaN-on-silicon enablingGaN power electronics, but to capture less than 5%of LED making by 2020" (PDF). Compounds & AdvancedSilicon. 9 (April/May 2014). SeminconductorTODAY.
  33. ^ Rahbardar Mojaver, Hassan; Gosselin, Jean-Lou; Valizadeh, Pouya (27 June 2017). "Use of a bilayer lattice-matched AlInGaN barrier for improving the channel carrier confinement of enhancement-mode AlInGaN/GaN hetero-structure field-effect transistors". Journal of Applied Physics. 121 (24): 244502. Bibcode:2017JAP...121x4502R. doi:10.1063/1.4989836. ISSN 0021-8979.
  34. ^ "GaN Power ICs". Navitas.
  35. ^ "GaN Integrated Circuits". EPC.
  36. ^ "HRL Laboratories claims first gallium nitride CMOS transistor fabrication". www.semiconductor-today.com.
  37. ^ "GaN: Pushing the limits of power density & efficiency | TI.com". www.ti.com. Retrieved 11 July 2024.
  38. ^ "Simplifying Power Conversion in High-Voltage Systems". Texas Instruments. Retrieved 11 July 2024.
  39. ^ "Apple 30W Compact GaN Charger". Retrieved 30 April 2022.
  40. ^ 2010 IEEE Intl. Symposium, Technical Abstract Book, Session TH3D, pp. 164–165
  41. ^ a b c Davis, Sam (1 November 2009). "SiC and GaN Vie for Slice of the Electric Vehicle Pie". Power Electronics. Archived from the original on 20 November 2021. Retrieved 3 January 2016. These devices offer lower loss during power conversion and operational characteristics that surpass traditional silicon counterparts.
  42. ^ "Making the new silicon: Gallium nitride electronics could drastically cut energy usage". Retrieved 28 June 2018.
  43. ^ Meneghini, Matteo; Hilt, Oliver; Wuerfl, Joachim; Meneghesso, Gaudenzio (25 January 2017). "Technology and Reliability of Normally-Off GaN HEMTs with p-Type Gate". Energies. 10 (2): 153. doi:10.3390/en10020153. hdl:11577/3259344.
  44. ^ "Gallium Nitride-Based Modules Set New 180-Day Standard For High Power Operation." Northrop Grumman, 13 April 2011.
  45. ^ Pocock, Chris. "Export Market Strong for Thales Ground Radar". Aviation International News. Retrieved 28 May 2021.
  46. ^ a b Brown, Jack (16 October 2018). "GaN Extends Range of Army's Q-53 Radar System". Microwaves&RF. Retrieved 23 July 2019.
  47. ^ Martin, Lockheed. "U.S. Army Awards Lockheed Martin Contract Extending AN/TPQ-53 Radar Range". Lockheed Martin. Retrieved 23 July 2019.
  48. ^ Martin, Lockheed. "AN/TPQ-53 Radar System". Lockheed Martin. Retrieved 23 July 2019.
  49. ^ Martin, Lockheed. "Lockheed Martin Demonstrates Mature, Proven Radar Technology During U.S. Army's Sense-Off". Lockheed Martin. Retrieved 23 July 2019.
  50. ^ "Gripen C/D Flies with Saab's new AESA Radar for the First Time". Archived from the original on 2 May 2020.
  51. ^ "Saab first in its industry to bring GaN to market". Archived from the original on 6 February 2016.
  52. ^ "Saab's Giraffe 1X Radar Offers a Man-Portable 75km Detection Range". Archived from the original on 23 August 2020.
  53. ^ "Saab Receives Swedish Order for Giraffe 4A and Arthur Radars". Archived from the original on 5 December 2018.
  54. ^ "Arexis - Outsmarting threats by electronic attack". Archived from the original on 23 August 2020.
  55. ^ "Saab to Supply Key Components in Support of the U.S. Marine Corps Ground/Air Task Oriented Radar (G/ATOR) Program". 12 February 2015. Archived from the original on 31 October 2020.
  56. ^ "Air Force to equip Su-30MKI fleet with indigenous 'Virupaaksha' radar". India Today. 19 October 2023. Retrieved 10 October 2024.
  57. ^ "India's Next-Gen Virupaksha AESA Beam & Radar Steering Radar To Revolutionise Su-30MKI Jets". Retrieved 10 October 2024.
  58. ^ alphadefense.in (8 October 2024). "Monstrous Virupaksha Radar of Su30 MKI Upgrade". alphadefense.in. Retrieved 10 October 2024.
  59. ^ Goldberger, J.; He, R.; Zhang, Y.; Lee, S.; Yan, H.; Choi, H. J.; Yang, P. (2003). "Single-crystal gallium nitride nanotubes". Nature. 422 (6932): 599–602. Bibcode:2003Natur.422..599G. doi:10.1038/nature01551. PMID 12686996. S2CID 4391664.
  60. ^ Zhao, Chao; Alfaraj, Nasir; Subedi, Ram Chandra; Liang, Jian Wei; Alatawi, Abdullah A.; Alhamoud, Abdullah A.; Ebaid, Mohamed; Alias, Mohd Sharizal; Ng, Tien Khee; Ooi, Boon S. (2019). "III–nitride nanowires on unconventional substrates: From materials to optoelectronic device applications". Progress in Quantum Electronics. 61: 1–31. doi:10.1016/j.pquantelec.2018.07.001. hdl:10754/628417.
  61. ^ Ralf Riedel, I-Wei Chen (2015). Ceramics Science and Technology, Volume 2: Materials and Properties. Wiley-Vch. ISBN 978-3527802579.
  62. ^ Jian-Jang Huang, Hao-Chung Kuo, Shyh-Chiang Shen (2014). Nitride Semiconductor Light-Emitting Diodes (LEDs). Woodhead. p. 68. ISBN 978-0857099303.{{cite book}}: CS1 maint: multiple names: authors list (link)
  63. ^ M. Shibata, T. Furuya, H. Sakaguchi, S. Kuma (1999). "Synthesis of gallium nitride by ammonia injection into gallium melt". Journal of Crystal Growth. 196 (1): 47–52. Bibcode:1999JCrGr.196...47S. doi:10.1016/S0022-0248(98)00819-7.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  64. ^ US8357945B2, D'Evelyn, Mark Philip; Park, Dong-Sil & LeBoeuf, Steven Francis et al., "Gallium nitride crystal and method of making same", issued 2013-01-22 
  65. ^ "Google Patents". patents.google.com. Retrieved 20 October 2022.
  66. ^ Murata, Junji; Nishiguchi, Yoshito; Iwasaki, Takeshi (1 December 2018). "Liquid electrolyte-free electrochemical oxidation of GaN surface using a solid polymer electrolyte toward electrochemical mechanical polishing". Electrochemistry Communications. 97: 110–113. doi:10.1016/j.elecom.2018.11.006. ISSN 1388-2481.
  67. ^ Shenai-Khatkhate, D. V.; Goyette, R. J.; Dicarlo, R. L. Jr; Dripps, G. (2004). "Environment, health and safety issues for sources used in MOVPE growth of compound semiconductors". Journal of Crystal Growth. 272 (1–4): 816–21. Bibcode:2004JCrGr.272..816S. doi:10.1016/j.jcrysgro.2004.09.007.
  68. ^ Shipman, Matt and Ivanisevic, Albena (24 October 2011). "Research Finds Gallium Nitride is Non-Toxic, Biocompatible – Holds Promise For Biomedical Implants". North Carolina State University