Gallium(III) nitride
467198
226124757
2008-07-16T22:42:08Z
76.118.180.230
/* Generic */
{{Chembox new
| Name = Gallium(III) nitride
| IUPACName = Gallium(III) nitride
| OtherNames = None Listed.
| Name =
| Section1 = {{Chembox Identifiers
| CASNo = 25617-97-4
}}
| Section2 = {{Chembox Properties
| Formula = GaN
| MolarMass = 83.7297 g/mol
| Appearance = Yellow powder.
| Density = 6.15 g/cm<sup>3</sup>, solid
| Solubility = Reacts.
| MeltingPt = >2500°C<ref name=melting>[http://dx.doi.org/10.1063/1.1772878 Harafuji, Tsuchiya and Kawamura, J. Appl. Phys. 96, 2501-2512 (September 1, 2004)</ref>
| BoilingPt = -
| pKb = N/A
}}
| Section3 = {{Chembox Structure
| CrystalStruct = [[Wurtzite]], [[Cubic crystal system|Zinc Blende]], [[Cubic crystal system|Rock Salt]]
}}
| Section7 = {{Chembox Hazards
| EUClass = None listed.
| RPhrases = {{R36}}, {{R37}}, {{R38}}, {{R43}}.
| SPhrases = {{S24}}, {{S37}}.
| FlashPt = Non-flammable.
}}
| Section8 = {{Chembox Related
| OtherAnions = None listed.
| OtherCations = None listed.
| Function = [[base (chemistry)|base]]s
| OtherFunctn = None listed.
| OtherCpds = [[Boron nitride|BN]], [[indium nitride|InN]], [[Aluminium nitride|AlN]], [[Aluminium arsenide|AlAs]], [[Indium arsenide|InAs]],<br />
[[Gallium antimonide|GaSb]], [[Aluminium gallium arsenide|AlGaAs]], [[Indium gallium arsenide|InGaAs]],<br />
[[Gallium arsenide phosphide|GaAsP]], [[Gallium arsenide|GaAs]], [[Trimethylgallium|GaMe<sub>3</sub>]],<br />
[[Arsine|AsH<sub>3</sub>]], [[Gallium phosphide|GaP]]
}}
}}
'''Gallium nitride''' ({{Gallium}}{{Nitrogen}}) is a very hard material commonly used in bright [[Light Emitting Diodes|LEDs]] since the 1990s.
The [[compound (chemistry)|compound]] is a direct-bandgap [[semiconductor material]] of [[wurtzite]] crystal structure, with a wide (3.4 [[electronvolt|eV]]) [[band gap]], used in [[optoelectronic]], high-power and high-frequency devices. It is a binary [[boron group|group III]]/[[nitrogen group|group V]] [[direct bandgap]] [[semiconductor]]. 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. Because GaN transistors can operate at much hotter temperatures and work at much higher voltages than [[Gallium(III) arsenide|GaAs]] transistors, they make ideal power amplifiers at microwave frequencies.
==Physical properties==
GaN is a very hard, mechanically stable material with large [[heat capacity]].<ref name=doi10.1143/JJAP.36.5393>Isamu Akasaki and Hiroshi Amano, "Crystal Growth and Conductivity Control of Group III Nitride Semiconductors and Their Application to Short Wavelength Light Emitters", Jpn. J. Appl. Phys. Vol.36(1997) 5393-5408 {{doi|10.1143/JJAP.36.5393}}</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 >[http://www.osti.gov/bridge/product.biblio.jsp?osti_id=434361 Information Bridge: DOE Scientific and Technical Information - - Document #434361<!-- Bot generated title -->]</ref> to [[N-type semiconductor|N-type]] and with magnesium (Mg) to [[P-type semiconductor|P-type]],<ref name=doi10.1143/JJAP.28.L2112>Hiroshi Amano, Masahiro Kito, Kazumasa Hiramatsu and Isamu Akasaki, "P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron Beam Irradiation (LEEBI)", Jpn. J. Appl. Phys. Vol. 28 (1989) L2112-L2114, {{doi|10.1143/JJAP.28.L2112}}</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>Shinji Terao, Motoaki Iwaya, Ryo Nakamura, Satoshi Kamiyama, Hiroshi Amano and Isamu Akasaki, "Fracture of AlxGa1-xN/GaN Heterostructure —Compositional and Impurity Dependence—", Jpn. J. Appl. Phys. Vol. 40 (2001) L195-L197, {{doi|10.1143/JJAP.40.L195}}</ref> Gallium nitride compounds also tend to have a high spatial defect frequency, on the order of a hundred million to ten billion defects per square centimeter.<ref>[http://www.lbl.gov/Science-Articles/Archive/blue-light-diodes.html lbl.gov, blue-light-diodes]</ref>
GaN-based parts are very sensitive to [[electrostatic discharge]].<ref name=doi10.1143/JJAP.45.7565>Hajime Okumura, "Present Status and Future Prospect of Widegap Semiconductor High-Power Devices", Jpn. J. Appl. Phys. Vol. 45 (2006) 7565-7586, {{doi|10.1143/JJAP.45.7565}}</ref>
==Developments==
The high crystalline quality of GaN can be realized by low temperature deposited buffer layer technology.<ref>Applied Physics Letters, Volume 48, Issue 5, pp. 353-355 [http://link.aip.org/link/?APL/48/353]</ref> This high crystalline 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>Hiroshi Amano, Tsunemori Asahi and Isamu Akasaki, "Stimulated Emission Near Ultraviolet at Room Temperature from a GaN Film Grown on Sapphire by MOVPE Using an AlN Buffer Layer", Jpn. J. Appl. Phys. Vol. 29 (1990) L205-L206 {{doi|10.1143/JJAP.29.L205}}</ref> (indispensable for laser action).<ref name=doi10.1143/JJAP.34.L1517>Isamu Akasaki, Hiroshi Amano, Shigetoshi Sota, Hiromitsu Sakai, Toshiyuki Tanaka and Masayoshi Koike, "Stimulated Emission by Current Injection from an AlGaN/GaN/GaInN Quantum Well Device", Jpn. J. Appl. Phys. Vol.34(1995) L1517-L1519 {{doi|10.1143/JJAP.34.L1517}}</ref> This has led to the commercialization of high-performance blue LEDs and long-lifetime violet-laser diodes (LDs), and to the development of nitride-based devices such as UV detectors and high-speed [[field-effect transistor]]s.
High-brightness GaN light-emitting diodes (LEDs) completed the range of primary colors, and made applications such as daylight visible full-color LED displays, white LEDs and blue [[laser]] devices possible. The first GaN-based high-brightness LEDs were using a thin film of GaN deposited via [[MOCVD]] on [[sapphire]]. Other substrates used are [[zinc oxide]], with [[lattice constant]] mismatch only 2%, and [[silicon carbide]] (SiC).
Group III nitride semiconductors are recognized as one of the most promising materials for fabricating optical devices in the visible short-wavelength and UV region. Potential markets for high-power/high-frequency devices based on GaN include [[microwave]] [[radio-frequency]] power amplifiers (such as 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 than silicon transistors.The first Gallium Nitride metal/oxide semiconductor field-effect transistor (GaN MOSFET) was experimentally demonstrated by Weixiao Huang of Rensselaer Polytechnic Institute in early 2008<ref>Rensselaer Polytechnic Institute (2008). Weixiao Huang. Retrieved May 14, 2008, from http://www.eng.rpi.edu/lemelson/finalist_Huang.cfm</ref>
==Applications==
GaN, when doped with a suitable [[transition metal]] such as [[manganese]], is a promising [[spintronics]] material ([[magnetic semiconductor]]s).
[[Nanotube]]s of GaN are proposed for applications in nanoscale [[electronics]], optoelectronics and biochemical-sensing applications<ref name=nanotube>[http://dx.doi.org/10.1038/nature01551 Goldberger et al, Nature 422, 599-602 (10 April 2003)]</ref>
A GaN-based blue [[laser diode]] is used in the [[Blu-ray Disc|Blu-ray]] disc technologies, and in devices such as the [[Sony Computer Entertainment|Sony]] [[PlayStation 3]].
The mixture of GaN with [[indium|In]] ([[indium gallium nitride|InGaN]]) or [[Aluminium|Al]] ([[Aluminium gallium nitride|AlGaN]]) with a band gap dependent on ratio of In or Al to GaN allows to build light emitting diodes ([[LED]]s) with colors that can go from red to blue.
==Synthesis==
GaN crystals can be grown from a molten Na/Ga melt held under 100atm pressure of N<sub>2</sub> at 750<sup>o</sup>C. As Ga will not react with N<sub>2</sub> below 1000<sup>o</sup>C the powder must be made from something more reactive, and is usually made in one of the following ways:
Ga + NH<sub>3</sub> -> GaN + 3/2H<sub>2</sub><br />
Ga<sub>2</sub>O<sub>3</sub> + NH<sub>3</sub> -> GaN + H<sub>2</sub>O
==Safety and toxicity aspects==
The toxicology of GaN has not been fully investigated. The 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 recently in a review.<ref>Journal of Crystal Growth (2004); {{doi|doi:10.1016/j.jcrysgro.2004.09.007}}</ref>
==See also==
* [[Schottky diode]]
* [[Semiconductor devices]]
* [[Molecular-beam epitaxy]]
* [[Epitaxy]]
==References==
<references/>
==Further reading==
* [[Isamu Akasaki]] and Hiroshi Amano: "Breakthroughs in Improving Crystal Quality of GaN and Invention of the p–n Junction Blue-Light-Emitting Diode" Japanese Journal of Applied Physics, Vol. 45, No. 12, 2006, pp. 9001-9010.
*Isamu Akasaki and Hiroshi Amano: " Crystal Growth and Conductivity Control of Group III Nitride Semiconductors and Their Application to Short Wavelength Light Emitters" Japanese Journal of Applied Physics, Vol. 36, 1997, pp. 5393-5408.
* Shuji Nakamura, Gerhard Fasol, Stephen J. Pearton, ''The Blue Laser Diode : The Complete Story'', Springer; 2nd edition, October 2, 2000, (ISBN 3-540-66505-6)
* Jacques I. Pankove, T. D. Moustakas, ''Gallium Nitride (GaN) II: Semiconductors and Semimetals'', Academic Press, 1998 (ISBN 0-12-752166-6)
* [http://www.amazon.com/gp/product/3540665056/ Shuji Nakamura, Gerhard Fasol, Stephen J Pearton The Blue Laser Diode: The Complete Story, Springer Verlag, 2nd Edition (October 2, 2000)]
* [http://www.engineering.ucsb.edu/Announce/nakamura.html UCSB Press release describing Shuji Nakamura's work].
==External links==
===Generic===
* [http://mit.edu/tpalacios The Wide Bandgap Semiconductor Materials and Devices Group at MIT].
* [http://www.msm.cam.ac.uk/GaN/ The Cambridge center for galium nitride (GaN)].
* [http://www.tyndall.ie/gan Photonics Sources Group, Tyndall National Institute] GaN and other photonics research at the Tyndall National Institute, Ireland.
* [http://physchem.ox.ac.uk/MSDS/GA/gallium_nitride.html External MSDS Data Sheet].
* [http://www.ioffe.rssi.ru/SVA/NSM/Semicond/GaN/index.html Ioffe data archive]
* [http://www.onr.navy.mil/sci_tech/31/312/ncsr/materials/gan.asp National Compound Semiconductor Roadmap] page at ONR
* [http://www.nitronex.com/index.html Nitronex] Nitronex is a corporation that is manufacturing GaN on silicon RF power transistors and GaN on silicon epi wafers for sale.
* [http://www.semiconductor-today.com Semiconductor Today: Online resource covering compound semiconductors and advanced silicon materials and devices]
* [http://www.fbh-berlin.com/ Ferdinand-Braun-Institut für Höchstfrequenztechnik (FBH), Berlin].
===Commercial links===
* [http://electronicmaterials.rohmhaas.com/products/default.asp?product=Trimethylgallium Informative commercial link to Trimethylgallium and other metalorganics.]
* [http://electronicmaterials.rohmhaas.com/businesses/micro/metalorganics/vapor.asp?caid=291 Interactive Vapor Pressure Chart for metalorganics].
[[Category:Nitrides]]
[[Category:Gallium compounds]]
[[Category:Inorganic compounds]]
[[Category:Compound semiconductors]]
[[Category:Semiconductor materials]]
[[Category:III-V compounds]]
[[ar:نتريد غاليوم ثلاثي]]
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[[fr:Nitrure de gallium]]
[[it:Nitruro di gallio]]
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[[ja:窒化ガリウム]]
[[pl:Azotek galu]]