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Topic: Gallium arsenide

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In the News (Tue 18 Jun 19)

  DHHS (NIOSH) Publication No. 88-100
In the second phase of this study, a single dose of gallium arsenide partially dissociated when administered either intratracheally or orally to rats, releasing arsenic that was subsequently distributed, depending on the route of administration, to the lungs, blood, urine, and/or feces.
Gallium was found only in the lungs and feces, suggesting that some of the dissociated gallium was retained in the lung and that a portion was cleared by the mucociliary clearance mechanism and may have been subsequently swallowed.
Metabolism and excretion of orally and intraperitoneally administered gallium arsenide in the hamster.
www.cdc.gov /niosh/88-100.html   (2265 words)

 Method for the manufacture of gallium arsenide thin film solar cells - Patent 4657603
The present invention relates to a method for the manufacture of gallium arsenide thin film solar cells and in particular to a method wherein a germanium layer is applied to the substrate before the gallium arsenide layers are applied.
Deposition of a gallium arsenide layer 4 on the amorphous regions of the germanium-phosphorous layer 2 cannot occur due to the lack of lattice matching between the two layers.
The gallium aluminum arsenide layer 6, having a layer thickness of 0.5-l um, is p-type conductive and serves as a window layer.
www.freepatentsonline.com /4657603.html   (1898 words)

 Solar Energy Technologies Program: Single-Crystalline Thin Film
Gallium arsenide (GaAs) is a compound semiconductor: a mixture of two elements, gallium and arsenic.
Gallium is a by-product of the smelting of other metals, notably aluminum and zinc, and it is rarer than gold.
One of the greatest advantages of gallium arsenide and its alloys as PV cell materials is that it's amenable to a wide range of designs.
www.eere.energy.gov /solar/tf_single_crystalline.html   (509 words)

 Solar Cells - Gallium Arsenide Solar Cells
Gallium arsenide (GaAs) is a compound semiconductor, a mixture of two elements, gallium (Ga) and arsenic (As).
Gallium is a by-product of the smelting of other metals, notably aluminum and zinc, and is rare-rarer than gold, in fact.
Gallium arsenide for solar cells has been developing synergistically with gallium arsenide for light-emitting diodes, lasers, and other optoelectronic devices.
www.sandia.gov /pv/docs/PVFSCGallium_Arsenide_Solar_Cells.htm   (1090 words)

 The Scientist : Gallium Arsenide: Key To Faster, Better Computing
Gallium arsenide also has a high resistance to electrical current before it is doped with any impurities to form circuit elements.
Consequently, a gallium arsenide wafer, or substrate, is semi-insulating, whereas a silicon wafer is semi-conducting.
Gallium arsenide also offers a wider range of operating temperatures than silicon and much higher radiation hardness, which is a decisive advantage for military and space programs.
www.the-scientist.com /article/display/8854   (897 words)

  NTP: Abstract for TR-492: Gallium Arsenide
Gallium arsenide was nominated for study because of its widespread use in the microelectronics industry, the potential for worker exposure, and the absence of chronic toxicity data.
Gallium arsenide was not mutagenic in several strains of Salmonella typhimurium, with or without S9 metabolic activation enzymes, and no increase in the frequency of micronucleated erythrocytes was observed in peripheral blood of male or female mice exposed to gallium arsenide by inhalation for 14 weeks.
Exposure to gallium arsenide caused a spectrum of nonneoplastic lesions in the lung of rats and mice, the larynx of male rats and hyperplasia of the tracheobronchial lymph node in mice.
ntp.niehs.nih.gov /index.cfm?objectid=070AE8F0-EEFE-D19F-C4CA519B663EE1B8   (1896 words)

 Improved Class Of Gallium Arsenide Transistors May Lead To Higher Performance Wireless, Computer Applications
The major challenge in making gallium arsenide MOSFETs is perfecting the thin gate oxide material that's directly below the transistor's gate electrode, which receives electrical signal and acts as the transistor's switch by turning it on and off.
Beneath the gate oxide is the channel that's made from gallium arsenide.
Currently, most wireless applications use gallium arsenide metal-semiconductor field-effect transistors (MESFETs), which lack a gate oxide, but which are necessary because higher frequencies are attainable with gallium arsenide compared to silicon.
www.sciencedaily.com /releases/1998/12/981207233944.htm   (1032 words)

 Gallium Arsenide facts and figures
Gallium Arsenide (GaAs) is a compound semiconductor: a mixture of two elements, Gallium (Ga) and Arsenic (As).
Gallium is a byproduct of the smelting of other metals, notably aluminum and zinc, and it is rarer than gold.
Unlike silicon cells, Gallium Arsenide cells are relatively insensitive to heat.
www.logitech.uk.com /gallium_arsenide.asp   (296 words)

Further in vitro studies demonstrated the attenuation of gallium inhibition of hepatic and renal ALAD by zinc, suggesting that the mechanism of gallium action may involve competition for or displacement of zinc from the sulfhydryl group of the enzyme active site.
The plasma distribution of gallium (as an analogue of aluminium) was investigated in patients with Alzheimer disease, Down syndrome, or stroke dementia, in subjects on haemodialysis for chronic renal failure, and in healthy controls.
Gallium scintigraphy in both children demonstrated increased radionuclide concentration throughout the lungs, a pattern indistinguishable scintigraphically from that of Pneumocystis carinii pneumonia (PCP).
www.ithyroid.com /gallium.htm   (6276 words)

 NTP: Abstract for Teratology: Gallium arsenide
Gallium arsenide is a crystalline compound used extensively in the semiconductor industry.
Workers preparing solar cells and gallium arsenide ingots and wafers are potentially at risk from the inhalation of gallium arsenide dust.
Gallium and arsenic concentrations were determined in the maternal blood and uterine contents of the rats (3/group) at 7, 14, and 20 dg.
ntp-server.niehs.nih.gov /index.cfm?objectid=073074B1-AEA1-03C1-3F71F522BCBB6304   (612 words)

 Solar Energy Technologies Program: Single-Crystalline Thin Film
Gallium arsenide (GaAs) is a compound semiconductor: a mixture of two elements, gallium and arsenic.
Gallium is a by-product of the smelting of other metals, notably aluminum and zinc, and it is rarer than gold.
One of the greatest advantages of gallium arsenide and its alloys as PV cell materials is that it's amenable to a wide range of designs.
www1.eere.energy.gov /solar/tf_single_crystalline.html   (509 words)

 NTP: Abstract for Immunotoxicity of Gallium Arsenide
Gallium arsenide is used extensively in the semiconductor industry for the manufacture of various electronic components including light-emitting diodes.
Gallium arsenide suppressed the following immune parameters dose- dependently: the IgM and IgG (not shown) antibody response to sheep erythrocytes, the delayed hypersensitivity response to KLH, the mixed leukocyte response (MLR), and, to a lesser extent, splenic B lymphocyte numbers.
Exposure to gallium arsenide increased the resistance to Listeria monocytogenes and to a lesser extent, PYB6 tumor cell growth, while decreasing resistance to pulmonary burden of B16F10 melonoma.
ntp-server.niehs.nih.gov /index.cfm?objectid=03E85F0C-B9EF-16A9-CFD03661A3A7173B   (624 words)

 Wafer Technology: Gallium Arsenide   (Site not responding. Last check: )
Single crystal gallium arsenide is grown at low pressure from high purity polycrystalline gallium arsenide in a vertical temperature gradient.
Gallium arsenide can be supplied as ingots or ingot sections or as-cut, etched or polished wafers.
All gallium arsenide wafers are individually laser scribed with ingot and slice identity to ensure perfect traceability.
www.wafertech.co.uk /data/GaAs.html   (220 words)

 Gallium Arsenide - as a Photovoltaic Material
Gallium is a by-product of the smelting of other metals, notably aluminium and zinc, and it is rarer than gold.
Gallium arsenide's use in solar cells has been developing synergistically with its use in light-emitting diodes, lasers, and other optoelectronic devices.
Although the gallium indium phosphide (GaInP)/GaAs tandem cell has achieved an efficiency of 30% and is now commercially available for space applications, the cells have not yet been integrated into a concentrator system.
www.azom.com /details.asp?ArticleID=1166   (591 words)

 Scientists image 'magnetic semiconductors' on the nanoscale
Gallium arsenide, a semiconductor material used for high-performance devices in cell phones, becomes magnetic when manganese is added, but only at a temperature of -88 C (-126 F).
In order for it to be used in future computer chips, magnetic semiconductors like gallium manganese arsenide must remain magnetic at higher temperatures and also be made "cleaner," or less resistant to current flow.
By incorporating manganese atoms into the gallium arsenide semiconductor, the team has created an atomic-scale laboratory that can reveal what researchers have sought for decades: the precise interactions among atoms and electrons in chip materials.
www.eurekalert.org /pub_releases/2006-07/uoi-si072606.php   (917 words)

 American Elements: Gallium Supplier & Technical Information
Gallium is one of three elements that naturally occur as a liquid at room temperature.
Gallium is available as metal and compounds with purities from 99% to 99.9999% (ACS grade to ultra-high purity); metals in the form of foil, sputtering target, and rod, and compounds as submicron and nanopowder.
Nanosuspensions of alendronate with gallium or gadolinium attenuate neointimal hyperplasia in rats.
www.americanelements.com /ga.html   (534 words)

 Analyst Insight - The Growing Market for Gallium Arsenide Semiconductors
Gallium Arsenide (GaAs) is a compound semiconductor made up of Gallium and Arsenic.
Gallium, a rare chemical element, is made from the smelting of aluminum and arsenic.
Gallium Arsenide’s value as a semiconductor comes from its ability to conduct electricity faster than silicon (currently the most used semiconductor material).
www.taglichbrothers.com /analyst-insights/AI-JN-gallium-arsenide.htm   (1124 words)

 Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal   (Site not responding. Last check: )
Gallium arsenide (GaAs) is a compound of two elements, Gallium and Arsenic.
Single crystals of gallium arsenide can be manufactured by the Bridgeman technique, as the Czochralski process is difficult for this material due to its mechanical properties.
The environment, health and safety aspects of gallium arsenide sources (such as trimethylgallium and arsine) and industrial hygiene monitoring studies of metalorganic precursors have been reported recently in a review.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=gallium_arsenide   (760 words)

 Mineral Information Institute - GALLIUM
Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875.
Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be toxic.
Gallium is not produced from ore in the United States, but some is produced from scrap and impure metals.
www.mii.org /Minerals/photogallium.html   (582 words)

 It's Elemental - The Element Gallium
Trace amounts of gallium are found in diaspore, sphalerite, germanite and bauxite as well as in the byproducts of burning coal.
Gallium melts near room temperature and has one of the largest liquid ranges of any metal, so it has found use in high temperature thermometers.
Gallium is used as a doping material for semiconductors and has been used to produce solid-state items like transistors and light emitting diodes.
education.jlab.org /itselemental/ele031.html   (183 words)

 Chemistry : Periodic Table : gallium : key information
Ultra-pure gallium has a beautiful, silvery appearance, and the solid metal exhibits a conchoidal fracture similar to glass.
Gallium arsenide is capable of converting electricity directly into coherent light and gallium arsenide is a key component of LEDs (light emitting diodes).
Gallium is normally a byproduct of the manufacture of aluminium.
www.webelements.com /webelements/elements/text/Ga/key.html   (298 words)

 What is gallium arsenide? - a definition from Whatis.com - see also: GaAs
Gallium arsenide (chemical formula GaAs) is a semiconductor compound used in some diodes, field-effect transistors (FETs), and integrated circuits (ICs).
Gallium arsenide is used in the manufacture of light-emitting diodes (LEDs), which are found in optical communications and control systems.
Gallium arsenide can replace silicon in the manufacture of linear ICs and digital ICs.
whatis.techtarget.com /definition/0,,sid9_gci213980,00.html   (190 words)

 6.09: Crucial Tech
Alternatives to silicon such as germanium and gallium arsenide are appearing in a few specialized consumer products, thanks to recent strides in materials science.
If you put gallium arsenide on top of silicon you end up with crystal defects because silicon's lattice cells are smaller than gallium arsenide's.
Gallium arsenide can be used for optical components such as LEDs and tiny lasers called VCSELs (see "VCSELs," Wired 6.02, page 77).
www.wired.com /wired/archive/6.09/crucialtech_pr.html   (2358 words)

 M/A-COM III-V Materials Group: Growth and Properties of Very Large Crystals of SI GaAs   (Site not responding. Last check: )
It has been shown by Tower et al [1] and confirmed by Shibata et al [2] that the critical factor in the growth of long single crystals of GaAs is the turndown angle of the melt/solid interface at the periphery of the crystal.
Shibata postulated that the breakdown of crystal structure was due to the convergence of dislocations propagated perpendicular to the growth interface and hence focussed by the curved surface formed by a turndown at the periphery.
For gallium arsenide the density of the solid is less than that of the liquid.
www.macom-gaaswafers.com /GaAsIC2.html   (920 words)

 Motorola mixes silicon, gallium arsenide for super-chips | The Register
Gallium arsenide chips have been around for some time, but they are delicate and hard to produce.
Motorola has already produced 8in and 12in wafers containing chips built out of both silicon and gallium arsenide, and it hopes to start offering parts based on the new process "within a year or so".
It already reckons that a silicon-gallium arsenide chip costs about a tenth of what a pure gallium arsenide device costs to make.
www.theregister.co.uk /2001/09/04/motorola_mixes_silicon_gallium_arsenide   (510 words)

 Gallium Arsenide Wafers (GaAs Wafers) and GaAs Hall Sensor
Gallium Arsenide Wafers (GaAs Wafers) and GaAs Hall Sensor
Aluminum gallium arsenide wafers (AlGaAs wafers) for various LED chips or lamps for indoor and outdoor displays.
Aluminum gallium arsenide wafers (AlGaAs wafers) with good statbility on the epitaxial layer characteristics.
www.marubeni-sunnyvale.com /gaas_wafers.html   (326 words)

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