Editing Gallium nitride

{{Short description|Chemical semiconductor compound}}
{{About|Gallium nitride, the chemical compound||Gan (disambiguation){{!}}Gan}}
{{Use dmy dates|date=March 2018}}
{{Chembox
| Watchedfields = changed
| verifiedrevid = 476994965
| Name = Gallium nitride
| ImageFile = GaNcrystal.jpg
| ImageFile2 = GaN Wurtzite polyhedra.png
| IUPACName = Gallium nitride
| OtherNames = gallium(III) nitride
| Section1 =
 {{Chembox Identifiers
 | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
 | ChemSpiderID = 105057
 | InChI = 1/Ga.N/rGaN/c1-2
 | SMILES = [Ga]#N
 | SMILES1 = [Ga+3].[N-3]
 | InChIKey = JMASRVWKEDWRBT-MDMVGGKAAI
 | StdInChI_Ref = {{stdinchicite|correct|chemspider}}
 | StdInChI = 1S/Ga.N
 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
 | StdInChIKey = JMASRVWKEDWRBT-UHFFFAOYSA-N
 | CASNo = 25617-97-4
 | CASNo_Ref = {{cascite|correct|CAS}}
 | UNII_Ref = {{fdacite|correct|FDA}}
 | UNII = 1R9CC3P9VL
 | PubChem =  = LW9640000
 }}
| Section2 =
 {{Chembox Properties
 | Formula = GaN
 | MolarMass = 83.730 g/mol<ref name=b92/>
 | Appearance = yellow powder
 | Density = 6.1 g/cm<sup>3</sup><ref name=b92>{{RubberBible92nd|page=4.64}}</ref>
 | Solubility = Insoluble<ref>{{Cite journal|title=abstract NCSU study: Aqueous Stability of Ga- and N-Polar Gallium Nitride|journal=Langmuir|volume=29|issue=1|pages=216–220|doi=10.1021/la304039n|pmid=23227805|year = 2013|last1 = Foster|first1 = Corey M.|last2=Collazo|first2=Ramon|last3=Sitar|first3=Zlatko|last4=Ivanisevic|first4=Albena}}</ref>
 | MeltingPt = >&nbsp;1600&nbsp;°C<ref name=b92/><ref name=melting>{{cite journal|title = Molecular dynamics simulation for evaluating melting point of wurtzite-type GaN crystal| doi = 10.1063/1.1772878|journal = Journal of Applied Physics|volume = 96| page = 2501|year = 2004| issue = 5|bibcode = 2004JAP....96.2501H|last1 = Harafuji|first1 = Kenji|last2 = Tsuchiya|first2 = Taku|last3 = Kawamura|first3 = Katsuyuki }}</ref>
 | BoilingPt =
 | pKb =
 | BandGap = 3.4&nbsp;eV (300&nbsp;K, direct)
 | ElectronMobility = 1500&nbsp;cm<sup>2</sup>/(V·s) (300&nbsp;K)<ref>{{cite book|author4=Alex Lidow|author1=Johan Strydom|author2=Michael de Rooij|author3=David Reusch|title=GaN Transistors for efficient power conversion|date=2019|publisher=Wiley|location=California, USA|isbn=978-1-119-59442-0|page=3|edition=3}}</ref>
 | ThermalConductivity = 1.3&nbsp;W/(cm·K) (300&nbsp;K)<ref>Mion, Christian (2005). [http://repository.lib.ncsu.edu/ir/bitstream/1840.16/5418/1/etd.pdf "Investigation of the Thermal Properties of Gallium Nitride Using the Three Omega Technique"], Thesis, North Carolina State University.</ref>
 | RefractIndex = 2.429
 }}
| Section3 =
 {{Chembox Structure
 | CrystalStruct = [[Wurtzite (crystal structure)|Wurtzite]]
 | SpaceGroup = ''C''<sub>6v</sub><sup>4</sup>-''P''6<sub>3</sub>''mc''
 | Coordination = Tetrahedral
 | LattConst_a = 318.6&nbsp;pm
 | LattConst_c = 518.6&nbsp;pm<ref>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</ref>
 }}
| Section5 =
 {{Chembox Thermochemistry
 | DeltaHf = −110.2&nbsp;kJ/mol<ref name=b92t>{{RubberBible92nd|page=5.12}}</ref>
 | Entropy =
 | DeltaGf =
 | HeatCapacity =
 }}
| Section7 =
 {{Chembox Hazards
 | ExternalSDS = {{Sigma-Aldrich|id=481769|name=Gallium nitride|accessdate=18 February 2024}}
 | FlashPt = Non-flammable
 | GHSPictograms = {{GHS07}}
 | GHSSignalWord = Warning
 | HPhrases = {{H-phrases|317}}
 | PPhrases = {{P-phrases|261|272|280|302+352|321|333+313|501}}
 | NFPA-H = 2
 | NFPA-F = 0
 | NFPA-I = 0
 | NFPA_ref = <ref>{{cite web |url=https://www.fishersci.com/store/msds?partNumber=AA4021818&productDescription=GALL%28III%29+NITRIDE+99.99%25+50G&vendorId=VN00024248&countryCode=US&language=en|title=Safety Data Sheet|author=<!--Not stated-->|date=2020|website=fishersci.com|publisher=Thermo Fisher Science|access-date=18 February 2024}}
</ref>
 }}
| Section8 =
 {{Chembox Related
 | OtherAnions = [[Gallium phosphide]]<br />[[Gallium arsenide]]<br />[[Gallium antimonide]]
 | OtherCations = [[Boron nitride]]<br />[[Aluminium nitride]]<br />[[Indium nitride]]
 | OtherFunction_label =
 | OtherFunction =
 | OtherCompounds = [[Aluminium gallium arsenide]]<br />[[Indium gallium arsenide]]<br />[[Gallium arsenide phosphide]]<br />[[Aluminium gallium nitride]]<br />[[Indium gallium nitride]]
 }}
}}

'''Gallium nitride''' ('''{{chem2|auto=1|GaN}}''') is a binary [[boron group|III]]/[[nitrogen group|V]] [[direct bandgap]] [[semiconductor]] commonly used in blue [[light-emitting diode]]s since the 1990s. The [[compound (chemistry)|compound]] is a very hard material that has a [[Wurtzite crystal structure]]. Its wide [[band gap]] of 3.4&nbsp;[[electronvolt|eV]] affords it [[wide-bandgap semiconductor#Materials properties|special properties]] for applications in [[optoelectronic|optoelectronics]],<ref>{{Cite journal | last1 = Czelej | first1 = K. | title = 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 | doi = 10.1021/acs.chemmater.4c00178 | journal = Chemistry of Materials | volume = 36 | issue = 13 | pages = 6392–6409 | year = 2024| pmc = 11238542 }}</ref><ref>{{Cite journal | last1 = Di Carlo | first1 = A. | doi = 10.1002/1521-396X(200101)183:1<81::AID-PSSA81>3.0.CO;2-N | title = Tuning Optical Properties of GaN-Based Nanostructures by Charge Screening | journal = Physica Status Solidi A | volume = 183 | issue = 1 | pages = 81–85 | year = 2001 |bibcode = 2001PSSAR.183...81D }}</ref><ref>{{Cite journal | last1 = Arakawa | first1 = Y. | title = Progress in GaN-based quantum dots for optoelectronics applications | doi = 10.1109/JSTQE.2002.801675 | journal = IEEE Journal of Selected Topics in Quantum Electronics | volume = 8 | issue = 4 | pages = 823–832 | year = 2002 | bibcode = 2002IJSTQ...8..823A }}</ref> high-power and high-frequency devices. For example, GaN is the substrate that makes violet (405&nbsp;nm) laser diodes possible, without requiring nonlinear optical [[Second-harmonic generation|frequency doubling]].

Its sensitivity to [[ionizing radiation]] is low (like other [[boron group|group III]] [[nitride]]s), making it a suitable material for [[solar cell]] arrays for [[satellite]]s. Military and space applications could also benefit as [[Radiation hardening|devices have shown stability in high radiation environments]].<ref>{{cite web|title=Enhancement Mode Gallium Nitride (eGaN) FET Characteristics under Long Term Stress|url=http://epc-co.com/epc/documents/articles/eGaN_FET_Characteristics_under_Long_Term_Stress.pdf|author1=Lidow, Alexander |author2=Witcher, J. Brandon |author3=Smalley, Ken |location=GOMAC Tech Conference|date=March 2011}}</ref>

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 [[Terahertz radiation|THz]] devices.<ref>{{Cite journal|last=Ahi|first=Kiarash|date=September 2017|title=Review of GaN-based devices for terahertz operation|url=https://www.researchgate.net/publication/319639902|journal=Optical Engineering|volume=56|issue=9|pages=090901|via=SPIE|bibcode=2017OptEn..56i0901A|doi=10.1117/1.OE.56.9.090901|doi-access=free}}</ref> 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 supply|power supplies]] in electronic equipment, converting [[Alternating current|AC]] [[mains electricity]] to low-voltage [[Direct current|DC]].

== Physical properties ==
[[File:Crystal-GaN.jpg|thumb|left|GaN crystal]]

GaN is a very hard ([[Knoop hardness test|Knoop hardness]] 14.21&nbsp;GPa<ref name=GaNRZ>{{Cite web|url=http://web.eecs.umich.edu/~minar/pdf/GaN_review.pdf|title=Gallium Nitride as an Electromechanical Material. R-Z. IEEE 2014}}</ref>{{rp|4}}), mechanically stable [[wide-bandgap semiconductor]] material with high [[heat capacity]] and thermal conductivity.<ref name="doi10.1143/JJAP.36.5393">{{Cite journal | last1 = Akasaki | first1 = I. | last2 = Amano | first2 = H. | doi = 10.1143/JJAP.36.5393 | title = Crystal Growth and Conductivity Control of Group III Nitride Semiconductors and Their Application to Short Wavelength Light Emitters | journal = Japanese Journal of Applied Physics | volume = 36 | issue = 9A | pages = 5393 | year = 1997 |bibcode = 1997JaJAP..36.5393A | doi-access = free }}</ref> 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 constant]]s.<ref name="doi10.1143/JJAP.36.5393" /> GaN can be [[dopant|doped]] with [[silicon]] (Si) or with [[oxygen]]<ref name=ostidDE97001220 >Wetzel, C.; Suski, T.; Ager, J.W. III; Fischer, S.; Meyer, B.K.; Grzegory, I.; Porowski, S. (1996) [http://www.osti.gov/bridge/product.biblio.jsp?osti_id=434361 Strongly localized donor level in oxygen doped gallium nitride], International conference on physics of semiconductors, Berlin (Germany), 21–26 July 1996.</ref> to [[N-type semiconductor|n-type]] and with magnesium (Mg) to [[P-type semiconductor|p-type]].<ref name="doi10.1143/JJAP.28.L2112">{{Cite journal | last1 = Amano | first1 = H. | last2 = Kito | first2 = M. | last3 = Hiramatsu | first3 = K. | last4 = Akasaki | first4 = I. | title = P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron Beam Irradiation (LEEBI) | doi = 10.1143/JJAP.28.L2112 | journal = Japanese Journal of Applied Physics | volume = 28 | issue = 12 | pages = L2112 | year = 1989 |bibcode = 1989JaJAP..28L2112A | doi-access = free }}</ref><ref>{{Cite web |title=Discovery in gallium nitride a key enabler of energy efficient electronics |url=https://news.cornell.edu/stories/2019/09/discovery-gallium-nitride-key-enabler-energy-efficient-electronics |access-date=2022-10-20 |website=Cornell Chronicle |language=en}}</ref> However, the Si and Mg atoms change the way the GaN crystals grow, introducing [[tensile stress]]es and making them brittle.<ref name="doi10.1143/JJAP.40.L195">{{Cite journal | last1 = Terao | first1 = S. | last2 = Iwaya | first2 = M. | last3 = Nakamura | first3 = R. | last4 = Kamiyama | first4 = S. | last5 = Amano | first5 = H. | last6 = Akasaki | first6 = I. | doi = 10.1143/JJAP.40.L195 | title = Fracture of Al<sub>x</sub>Ga<sub>1−x</sub>N/GaN Heterostructure – Compositional and Impurity Dependence – | journal = Japanese Journal of Applied Physics | volume = 40 | issue = 3A | pages = L195 | year = 2001 | bibcode=2001JaJAP..40..195T| s2cid = 122191162 }}</ref> [[Gallium]] [[nitride]] compounds also tend to have a high [[dislocation]] density, on the order of 10<sup>8</sup> to 10<sup>10</sup> defects per square centimeter.<ref>Preuss, Paul (11 August 2000). [http://www.lbl.gov/Science-Articles/Archive/blue-light-diodes.html Blue Diode Research Hastens Day of Large-Scale Solid-State Light Sources] {{Webarchive|url=https://web.archive.org/web/20101025005330/http://www.lbl.gov/Science-Articles/Archive/blue-light-diodes.html |date=25 October 2010 }}. Berkeley Lab., lbl.gov.</ref>

The [[United States Army Research Laboratory|U.S. Army Research Laboratory]] (ARL) provided the first measurement of the high field electron [[velocity]] in GaN in 1999.<ref>{{cite journal |last1=Wraback |first1=M. |last2=Shen |first2=H. |last3=Carrano |first3=J.C. |last4=Collins |first4=C.J |last5=Campbell |first5=J.C. |last6=Dupuis |first6=R.D. |last7=Schurman |first7=M.J. |last8=Ferguson |first8=I.T. |title=Time-Resolved Electroabsorption Measurement of the electron velocity-field characteristic in GaN |journal=Applied Physics Letters |volume=76 |issue=9 |pages=1155–1157 |doi=10.1063/1.125968 |year=2000 |bibcode=2000ApPhL..76.1155W }}</ref> Scientists at ARL experimentally obtained a peak [[Steady state|steady-state]] velocity of {{val|1.9|e=7|u=cm/s}}, with a [[Transient state|transit]] time of 2.5 picoseconds, attained at an [[electric field]] of 225&nbsp;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.<ref>{{Cite web |last=Ahmad |first=Majeed |date=2023-05-23 |title=A brief history of gallium nitride (GaN) semiconductors |url=https://www.edn.com/a-brief-history-of-gallium-nitride-gan-semiconductors/ |access-date=2023-08-31 |website=EDN |language=en-US}}</ref>

An early synthesis of gallium nitride was by Robert Juza and Harry Hahn in 1938.<ref>{{cite journal | url=https://doi.org/10.1002/zaac.19382390307 | doi=10.1002/zaac.19382390307 | title=Über die Kristallstrukturen von Cu3N, GaN und InN Metallamide und Metallnitride | year=1938 | last1=Juza | first1=Robert | last2=Hahn | first2=Harry | journal=Zeitschrift für Anorganische und Allgemeine Chemie | volume=239 | issue=3 | pages=282–287 | url-access=subscription }}</ref>

GaN with a high crystalline quality can be obtained by depositing a buffer layer at low temperatures.<ref>{{Cite journal | last1 = Amano | first1 = H. | last2 = Sawaki | first2 = N. | last3 = Akasaki | first3 = I. | last4 = Toyoda | first4 = Y. | s2cid = 59066765 | title = Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer | doi = 10.1063/1.96549 | journal = Applied Physics Letters | volume = 48 | issue = 5 | pages = 353 | year = 1986 |bibcode = 1986ApPhL..48..353A }}</ref> Such high-quality GaN led to the discovery of p-type GaN,<ref name="doi10.1143/JJAP.28.L2112" /> p–n junction blue/UV-[[LED]]s<ref name="doi10.1143/JJAP.28.L2112" /> and room-temperature stimulated emission<ref name="doi10.1143/JJAP.29.L205">{{Cite journal | last1 = Amano | first1 = H. | last2 = Asahi | first2 = T. | last3 = Akasaki | first3 = I. | title = Stimulated Emission Near Ultraviolet at Room Temperature from a GaN Film Grown on Sapphire by MOVPE Using an AlN Buffer Layer | doi = 10.1143/JJAP.29.L205 | journal = Japanese Journal of Applied Physics | volume = 29 | issue = 2 | pages = L205 | year = 1990 |bibcode = 1990JaJAP..29L.205A | s2cid = 120489784 }}</ref> (essential for laser action).<ref name="doi10.7567/JJAP.34.L1517">{{Cite journal | last1 = Akasaki | first1 = I. | last2 = Amano | first2 = H. | last3 = Sota | first3 = S. | last4 = Sakai | first4 = H. | last5 = Tanaka | first5 = T. | last6 = Koike | first6 = M. | title = Stimulated Emission by Current Injection from an AlGaN/GaN/GaInN Quantum Well Device | doi = 10.7567/JJAP.34.L1517 | journal = Japanese Journal of Applied Physics | volume = 34 | number = 11B | pages = L1517 | year = 1995 | bibcode = 1995JaJAP..34L1517A }}</ref> 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 transistor]]s.{{cn|date=September 2023}}

=== 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).<ref name=review>{{Cite journal | last1 = Morkoç | first1 = H. | last2 = Strite | first2 = S. | last3 = Gao | first3 = G. B. | last4 = Lin | first4 = M. E. | last5 = Sverdlov | first5 = B. | last6 = Burns | first6 = M. | doi = 10.1063/1.358463 | title = Large-band-gap SiC, III–V nitride, and II–VI ZnSe-based semiconductor device technologies | journal = Journal of Applied Physics | volume = 76 | issue = 3 | pages = 1363 | year = 1994 |bibcode = 1994JAP....76.1363M }}</ref> 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.{{cn|date=September 2023}}

=== GaN transistors and power ICs ===
The very high [[breakdown voltages]],<ref>{{Cite journal | last1 = Dora | first1 = Y. | last2 = Chakraborty | first2 = A. | last3 = McCarthy | first3 = L. | last4 = Keller | first4 = S. | last5 = Denbaars | first5 = S. P. | last6 = Mishra | first6 = U. K. | doi = 10.1109/LED.2006.881020 | title = High Breakdown Voltage Achieved on AlGaN/GaN HEMTs with Integrated Slant Field Plates | journal = [[IEEE Electron Device Letters]] | volume = 27 | issue = 9 | pages = 713 | year = 2006 |bibcode = 2006IEDL...27..713D | s2cid = 38268864 }}</ref> 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 [[transistor]]s is as the microwave source for [[microwave oven]]s, replacing the [[magnetron]]s currently used. The large band gap means that the performance of GaN transistors is maintained up to higher temperatures (~400&nbsp;°C<ref name=GS-WGN>{{Cite web|url=https://gansystems.com/gan-transistors/about-gan-systems/|title=Why GaN Systems|date=29 November 2023 }}</ref>) than silicon transistors (~150&nbsp;°C<ref name=GS-WGN/>) because it lessens the effects of [[Electrical resistivity and conductivity#In semiconductors and insulators|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<ref>{{Cite journal | last1 = Asif Khan | first1 = M. | last2 = Kuznia | first2 = J. N. | last3 = Bhattarai | first3 = A. R. | last4 = Olson | first4 = D. T. | title = Metal semiconductor field effect transistor based on single crystal GaN | doi = 10.1063/1.109549 | journal = Applied Physics Letters | volume = 62 | issue = 15 | pages = 1786 | year = 1993 |bibcode = 1993ApPhL..62.1786A }}</ref> and they are being actively developed.

In 2010, the first [[enhancement-mode]] GaN transistors became generally available.<ref name=EPC-EM-2010>{{cite journal|last=Davis|first=Sam|title=Enhancement Mode GaN MOSFET Delivers Impressive Performance|journal=Electronic Design|date=March 2010|volume=36|issue=3|url=https://www.electronicdesign.com/technologies/discrete-power-semis/article/21191975/enhancement-mode-gallium-nitride-mosfet-delivers-impressive-performance}}</ref> Only n-channel transistors were available.<ref name=EPC-EM-2010/> 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.<ref>{{Cite journal|title=GaN-on-silicon enablingGaN power electronics, but to capture less than 5%of LED making by 2020|url=http://www.semiconductor-today.com/features/PDF/SemiconductorToday_AprMay2014-GaN-on-silicon.pdf|journal=Compounds & AdvancedSilicon|publisher=SeminconductorTODAY|volume=9|issue=April/May 2014}}</ref> This allows the FETs to maintain costs similar to silicon power MOSFETs but with the superior electrical performance of GaN, and consists of growing GaN on silicon wafers using MOCVD Epitaxy.<ref>https://www.powerelectronicsnews.com/infineon-advances-gan-technology-with-300-mm-wafer-production/</ref> 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.<ref>{{Cite journal|last1=Rahbardar Mojaver|first1=Hassan|last2=Gosselin|first2=Jean-Lou|last3=Valizadeh|first3=Pouya|date=2017-06-27|title=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=Journal of Applied Physics|volume=121|issue=24|pages=244502|doi=10.1063/1.4989836|bibcode=2017JAP...121x4502R |issn=0021-8979}}</ref>

GaN power ICs monolithically integrate a GaN FET, GaN-based drive circuitry and circuit protection into a single surface-mount device.<ref>{{cite web |title=GaN Power ICs |url=https://www.navitassemi.com/gan-power-ics/ |website=Navitas}}</ref><ref>{{cite web |title=GaN Integrated Circuits |url=https://epc-co.com/epc/Products/eGaNFETsandICs/eGaNIntegratedCircuits/ |website=EPC}}</ref>  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&nbsp;μm (gate widths of the PMOS and NMOS transistors were 500&nbsp;μm and 50&nbsp;μm, respectively).<ref name=sct-2016-cmos>{{Cite web|url=https://www.semiconductor-today.com/news_items/2016/feb/hrl_150216.shtml|title=HRL Laboratories claims first gallium nitride CMOS transistor fabrication|website=www.semiconductor-today.com}}</ref>

== Applications ==
=== LEDs and lasers ===
GaN-based violet [[laser diode]]s are used to read [[Blu-ray Disc]]s.  The mixture of GaN with [[indium|In]] ([[indium gallium nitride|InGaN]]) or [[Aluminium|Al]] ([[Aluminium gallium nitride|AlGaN]]) with a band gap dependent on the ratio of In or Al to GaN allows the manufacture of light-emitting diodes ([[LED]]s) with colors that can go from red to ultra-violet.<ref name=review/>

=== Transistors and power ICs ===
[[File:FBH GaN High electron mobility transistor.jpg|thumb|GaN [[high-electron-mobility transistor]]s (manufactured by [[Ferdinand-Braun-Institut]])]]
GaN transistors are suitable for high frequency, high voltage, high temperature and high-efficiency applications.<ref>{{Cite web |title=GaN: Pushing the limits of power density & efficiency {{!}} TI.com |url=https://www.ti.com/technologies/gallium-nitride.html |access-date=2024-07-11 |website=www.ti.com |language=en-US}}</ref><ref>{{Cite web |title=Simplifying Power Conversion in High-Voltage Systems |url=https://www.ti.com/lit/SLYY221 |access-date=11 July 2024 |website=Texas Instruments}}</ref> GaN is efficient at transferring current, and this ultimately means that less energy is lost to heat. <ref>{{Cite news|url=https://manmadecycle.com.au/blogs/news/apple-30w-compact-gan-charger|title=Apple 30W Compact GaN Charger|access-date=2022-04-30|language=en}}</ref>

GaN [[high-electron-mobility transistor]]s (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.<ref>2010 IEEE Intl. Symposium, Technical Abstract Book, Session TH3D, pp. 164–165</ref>

GaN-based metal–oxide–semiconductor field-effect transistors ([[MOSFET]]) and metal–semiconductor field-effect transistors ([[MESFET]]) also offer advantages including lower loss in high power electronics, especially in automotive and electric car applications.<ref name="Davis2009">{{Cite web
| title = SiC and GaN Vie for Slice of the Electric Vehicle Pie
| first = Sam
| last = Davis
| work = Power Electronics
| date = 2009-11-01
| access-date = 2016-01-03
| url = http://powerelectronics.com/passive-components/sic-and-gan-vie-slice-electric-vehicle-pie
| quote = These devices offer lower loss during power conversion and operational characteristics that surpass traditional silicon counterparts.
| archive-date = 20 November 2021
| archive-url = https://web.archive.org/web/20211120210913/https://www.powerelectronics.com/passive-components/sic-and-gan-vie-slice-electric-vehicle-pie
| url-status = dead
}}</ref> Since 2008 these can be formed on a silicon substrate.<ref name="Davis2009"/> High-voltage (800&nbsp;V) [[Schottky barrier diode]]s (SBDs) have also been made.<ref name="Davis2009"/>

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]] [[public utility|utilities]].

Unlike silicon transistors that switch off due to power surges,{{clarify|date=May 2024|reason=A 'power surge' in this context makes no sense.}} 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:<ref>{{Cite news|url=https://phys.org/news/2015-07-silicon-gallium-nitride-electronics-drastically.html|title=Making the new silicon: Gallium nitride electronics could drastically cut energy usage|access-date=2018-06-28}}</ref><ref>{{Cite journal|last1=Meneghini|first1=Matteo|last2=Hilt|first2=Oliver|last3=Wuerfl|first3=Joachim|last4=Meneghesso|first4=Gaudenzio|date=2017-01-25|title=Technology and Reliability of Normally-Off GaN HEMTs with p-Type Gate|journal=Energies|language=en|volume=10|issue=2|pages=153|doi=10.3390/en10020153|doi-access=free|hdl=11577/3259344|hdl-access=free}}</ref>
* 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<!-- how is this better than the ones made in 2010 in the section above ? -->

=== Radars ===
GaN technology is also utilized in military electronics such as [[active electronically scanned array]] radars.<ref>[http://www.spacewar.com/reports/Gallium_Nitride_Based_Modules_Set_New_180_Day_Standard_For_High_Power_Operation_999.html "Gallium Nitride-Based Modules Set New 180-Day Standard For High Power Operation."] ''Northrop Grumman'', 13 April 2011.</ref>

[[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.<ref>{{Cite web|last=Pocock|first=Chris|title=Export Market Strong for Thales Ground Radar|url=https://www.ainonline.com/aviation-news/defense/2016-02-12/export-market-strong-thales-ground-radar|access-date=2021-05-28|website=Aviation International News|language=en}}</ref>

The [[United States Army|U.S. Army]] funded [[Lockheed Martin]] to incorporate GaN active-device technology into the [[AN/TPQ-53 Quick Reaction Capability Radar|AN/TPQ-53]] radar system to replace two medium-range radar systems, the [[AN/TPQ-36 Firefinder radar|AN/TPQ-36]] and the [[AN/TPQ-37 Firefinder radar|AN/TPQ-37]].<ref name="mwrf.com">{{cite web |last1=Brown |first1=Jack |title=GaN Extends Range of Army's Q-53 Radar System |url=https://www.mwrf.com/defense/gan-extends-range-army-s-q-53-radar-system |website=Microwaves&RF |access-date=23 July 2019|date=16 October 2018 }}</ref><ref>{{cite web |last1=Martin|first1=Lockheed |title=U.S. Army Awards Lockheed Martin Contract Extending AN/TPQ-53 Radar Range |url=https://news.lockheedmartin.com/2018-10-08-U-S-Army-Awards-Lockheed-Martin-Contract-Extending-AN-TPQ-53-Radar-Range |website=Lockheed Martin |access-date=23 July 2019}}</ref> The AN/TPQ-53 radar system was designed to detect, classify, track, and locate enemy indirect fire systems, as well as unmanned aerial systems.<ref>{{cite web |last1=Martin|first1=Lockheed |title=AN/TPQ-53 Radar System |url=https://www.lockheedmartin.com/en-us/products/tpq-53.html |website=Lockheed Martin |access-date=23 July 2019}}</ref> 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.<ref name="mwrf.com"/>

Lockheed Martin fielded other tactical operational radars with GaN technology in 2018, including [[FPS-117#AN/TPS-77|TPS-77 Multi Role Radar System]] deployed to [[Latvia]] and [[Romania]].<ref>{{cite web |last1=Martin |first1=Lockheed |title=Lockheed Martin Demonstrates Mature, Proven Radar Technology During U.S. Army's Sense-Off |url=https://news.lockheedmartin.com/2019-06-18-Lockheed-Martin-Demonstrates-Mature-Proven-Radar-Technology-During-U-S-Armys-Sense-Off |website=Lockheed Martin |access-date=23 July 2019}}</ref> In 2019, Lockheed Martin's partner [[Elta Systems|ELTA Systems Limited]], developed a GaN-based [[EL/M-2084|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 AB|Saab]] flight tested its new GaN designed [[Active electronically scanned array|AESA]] [[X band|X-band]] radar in a [[Saab JAS 39 Gripen|JAS-39 Gripen]] fighter.<ref>{{cite web |url=https://saab.com/gripen/news/blog/gripen-blog/2020/gripen-cd-flies-with-saabs-new-aesa-radar-for-the-first-time/ |title=Gripen C/D Flies with Saab's new AESA Radar for the First Time |archive-url=https://web.archive.org/web/20200502142704/https://saab.com/gripen/news/blog/gripen-blog/2020/gripen-cd-flies-with-saabs-new-aesa-radar-for-the-first-time/ |archive-date=2020-05-02}}</ref> Saab already offers products with GaN based radars, like the [[Giraffe radar]], [[Erieye]], [[GlobalEye]], and Arexis EW.<ref>{{cite web |url=https://saabgroup.com/media/stories/stories-listing/stories-of-innovation/innovation-prize/ |title=Saab first in its industry to bring GaN to market |archive-url=https://web.archive.org/web/20160206010619/https://saabgroup.com/media/stories/stories-listing/stories-of-innovation/innovation-prize/ |archive-date=2016-02-06}}</ref><ref>{{cite web |url=https://saabgroup.com/media/news-press/news/2018-04/saabs-giraffe-1x-radar-offers-a-man-portable-75km-detection-range/ |title=Saab's Giraffe 1X Radar Offers a Man-Portable 75km Detection Range |archive-url=https://web.archive.org/web/20200823213125/https://saabgroup.com/media/news-press/news/2018-04/saabs-giraffe-1x-radar-offers-a-man-portable-75km-detection-range/ |archive-date=2020-08-23}}</ref><ref>{{cite web |url=https://saabgroup.com/media/news-press/news/2018-12/saab-receives-swedish-order-for-giraffe-4a-and-arthur-radars/ |title= Saab Receives Swedish Order for Giraffe 4A and Arthur Radars |archive-url=https://web.archive.org/web/20181205183526/https://saabgroup.com/media/news-press/news/2018-12/saab-receives-swedish-order-for-giraffe-4a-and-arthur-radars/ |archive-date=2018-12-05}}</ref><ref>{{cite web |url=https://saabgroup.com/media/stories/stories-listing/2020-07/outsmarting-threats-by-electronic-attack/ |title=Arexis - Outsmarting threats by electronic attack |archive-url=https://web.archive.org/web/20200823214914/https://saabgroup.com/media/stories/stories-listing/2020-07/outsmarting-threats-by-electronic-attack/ |archive-date=2020-08-23 }}</ref> Saab also delivers major subsystems, assemblies and software for the  [[AN/TPS-80 Ground/Air Task Oriented Radar|AN/TPS-80 (G/ATOR)]]<ref>{{cite web |url=https://www.saab.com/newsroom/press-releases/2015/saab-to-supply-key-components-in-support-of-the-u.s.-marine-corps-groundair-task-oriented-radar-gator-program |title=Saab to Supply Key Components in Support of the U.S. Marine Corps Ground/Air Task Oriented Radar (G/ATOR) Program |archive-url=https://web.archive.org/web/20201031164750/https://www.saab.com/newsroom/press-releases/2015/saab-to-supply-key-components-in-support-of-the-u.s.-marine-corps-groundair-task-oriented-radar-gator-program |archive-date=2020-10-31 |url-status=live |date=Feb 12, 2015}}</ref>

India's [[Defence Research and Development Organisation]] is developing [[Uttam AESA Radar#Virupaakhsha|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 [[Gallium arsenide|GaAs]] technology. <ref>{{Cite web |date=2023-10-19 |title=Air Force to equip Su-30MKI fleet with indigenous 'Virupaaksha' radar |url=https://www.indiatoday.in/india/story/su-30mki-fighters-air-force-to-equip-its-fleet-with-indigenous-virupaksha-radar-2451237-2023-10-19 |access-date=2024-10-10 |website=India Today |language=en}}</ref><ref>{{Cite web |title=India's Next-Gen Virupaksha AESA Beam & Radar Steering Radar To Revolutionise Su-30MKI Jets |url=https://www.indiandefensenews.in/2024/08/indias-next-gen-virupaksha-aesa-beam.html?m=1 |access-date=2024-10-10}}</ref><ref>{{Cite web |last=alphadefense.in |date=2024-10-08 |title=Monstrous Virupaksha Radar of Su30 MKI Upgrade |url=https://alphadefense.in/index.php/2024/10/09/monstrous-virupaksha-radar-of-su30-mki-upgrade/?amp=1 |access-date=2024-10-10 |website=alphadefense.in |language=en-US}}</ref>

=== Nanoscale ===
[[gallium nitride nanotube|GaN nanotube]]s and nanowires are proposed for applications in nanoscale [[electronics]], optoelectronics and biochemical-sensing applications.<ref name=nanotube>{{Cite journal | last1 = Goldberger | first1 = J. | last2 = He | first2 = R. | last3 = Zhang | first3 = Y. | last4 = Lee | first4 = S. | last5 = Yan | first5 = H. | last6 = Choi | first6 = H. J. | last7 = Yang | first7 = P. | doi = 10.1038/nature01551 | title = Single-crystal gallium nitride nanotubes | journal = Nature | volume = 422 | issue = 6932 | pages = 599–602 | year = 2003 | pmid =  12686996|bibcode = 2003Natur.422..599G | s2cid = 4391664 }}</ref><ref name="zhao2018III">{{cite journal |last1=Zhao |first1=Chao |last2=Alfaraj |first2=Nasir |last3=Subedi |first3=Ram Chandra |last4=Liang |first4=Jian Wei |last5=Alatawi |first5=Abdullah A. |last6=Alhamoud |first6=Abdullah A. |last7=Ebaid |first7=Mohamed |last8=Alias |first8=Mohd Sharizal |last9=Ng |first9=Tien Khee |last10=Ooi |first10=Boon S. |title=III–nitride nanowires on unconventional substrates: From materials to optoelectronic device applications |journal=Progress in Quantum Electronics |date=2019 |volume=61 |pages=1–31 |doi=10.1016/j.pquantelec.2018.07.001 |doi-access=free |hdl=10754/628417 |hdl-access=free }}</ref>

=== Spintronics potential ===
When doped with a suitable [[transition metal]] such as [[manganese]], GaN is a promising [[spintronics]] material ([[magnetic semiconductor]]s).<ref name=review/>

== Synthesis ==
=== Bulk substrates ===
GaN crystals can be grown from a molten Na/Ga melt held under 100 atmospheres of pressure of N<sub>2</sub> at 750&nbsp;°C. As Ga will not react with N<sub>2</sub> below 1000&nbsp;°C, the powder must be made from something more reactive, usually in one of the following ways:
: 2 Ga + 2 NH<sub>3</sub> → 2 GaN + 3 H<sub>2</sub><ref>{{cite book | title=Ceramics Science and Technology, Volume 2: Materials and Properties | isbn=978-3527802579 | author=Ralf Riedel, I-Wei Chen| date=2015 | publisher=Wiley-Vch}}</ref>
: Ga<sub>2</sub>O<sub>3</sub> + 2 NH<sub>3</sub> → 2 GaN + 3 H<sub>2</sub>O<ref>{{cite book | title=Nitride Semiconductor Light-Emitting Diodes (LEDs) | isbn=978-0857099303 | author=Jian-Jang Huang, Hao-Chung Kuo, Shyh-Chiang Shen |pages=68 | date= 2014| publisher=Woodhead }}</ref>

Gallium nitride can also be synthesized by injecting ammonia gas into molten gallium at {{val|900|-|980|u=°C}} at normal atmospheric pressure.<ref>{{cite journal | title=Synthesis of gallium nitride by ammonia injection into gallium melt | author=M. Shibata, T. Furuya, H. Sakaguchi, S. Kuma | doi=10.1016/S0022-0248(98)00819-7 | journal=Journal of Crystal Growth | volume=196 | issue=1 | pages=47–52| date=1999| bibcode=1999JCrGr.196...47S}}</ref>

=== Metal-organic vapour phase epitaxy ===
Blue, white and ultraviolet [[Light-emitting diode|LED]]s are grown on industrial scale by [[Metalorganic vapour-phase epitaxy|metalorganic vapour-phase epitaxy (MOVPE)]].<ref>{{Cite patent|number=US8357945B2|title=Gallium nitride crystal and method of making same|gdate=2013-01-22|invent1=D'Evelyn|invent2=Park|invent3=LeBoeuf|invent4=Rowland|inventor1-first=Mark Philip|inventor2-first=Dong-Sil|inventor3-first=Steven Francis|inventor4-first=Larry Burton|url=https://patents.google.com/patent/US8357945B2/en}}</ref><ref>{{Cite web |title=Google Patents |url=https://patents.google.com/?q=gallium+nitride&assignee=cornell |access-date=2022-10-20 |website=patents.google.com}}</ref> The precursors are [[ammonia]] with either [[trimethylgallium]] or [[triethylgallium]], the carrier gas being [[nitrogen]] or [[hydrogen]]. Growth temperature ranges between {{val|800|and|1100|u=°C}}. Introduction of [[trimethylaluminium]] and/or [[trimethylindium]] is necessary for growing quantum wells and other kinds of [[heterostructure]]s.

=== Molecular beam epitaxy ===
Commercially, GaN crystals can be grown using [[molecular beam epitaxy]] or MBE. 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.<ref>{{Cite journal|date=2018-12-01|title=Liquid electrolyte-free electrochemical oxidation of GaN surface using a solid polymer electrolyte toward electrochemical mechanical polishing|journal=Electrochemistry Communications|language=en|volume=97|pages=110–113|doi=10.1016/j.elecom.2018.11.006|issn=1388-2481|doi-access=free|last1=Murata |first1=Junji |last2=Nishiguchi |first2=Yoshito |last3=Iwasaki |first3=Takeshi }}</ref>

== 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.<ref>{{Cite journal | last1 = Shenai-Khatkhate | first1 = D. V. | last2 = Goyette | first2 = R. J. | last3 = Dicarlo | first3 = R. L. Jr| last4 = Dripps  | first4 = G. | title = Environment, health and safety issues for sources used in MOVPE growth of compound semiconductors | doi = 10.1016/j.jcrysgro.2004.09.007 | journal = Journal of Crystal Growth | volume = 272 | issue = 1–4 | pages = 816–21 | year = 2004 | bibcode = 2004JCrGr.272..816S}}</ref>

Bulk GaN is non-toxic and [[biocompatible]].<ref>Shipman, Matt and Ivanisevic, Albena (24 October 2011). [https://web.archive.org/web/20140429215300/http://news.ncsu.edu/releases/wmsivanisevicganpeptides/ "Research Finds Gallium Nitride is Non-Toxic, Biocompatible – Holds Promise For Biomedical Implants"]. North Carolina State University</ref> Therefore, it may be used in the electrodes and electronics of implants in living organisms.

== See also ==
* [[Schottky diode]]
* [[Semiconductor devices]]
* [[Molecular-beam epitaxy]]
* [[Epitaxy]]
* [[Lithium-ion battery]]

== References ==
{{reflist}}

== External links ==
{{Commons category|Gallium nitride}}
* [http://www.ioffe.rssi.ru/SVA/NSM/Semicond/GaN/index.html Ioffe data archive]

{{Gallium compounds}}
{{Nitrides}}
{{Authority control}}

{{DEFAULTSORT:Gallium Nitride}}
[[Category:Nitrides]]
[[Category:Gallium compounds]]
[[Category:Inorganic compounds]]
[[Category:III-V semiconductors]]
[[Category:Wurtzite structure type]]