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Topic: Arsenide


In the News (Tue 21 May 19)

  
  Gallium arsenide - Wikipedia, the free encyclopedia
Gallium arsenide (GaAs) is a chemical compound composed of gallium and arsenic.
By combining gallium arsenide with germanium and indium gallium phosphide, it is possible to realise a triple junction solar cell which holds the record efficiency of over 32% and can operate also with concentrated light up to 2.000 suns.
Single crystals of gallium arsenide are manufactured by the Bridgeman technique, as the Czochralski process is difficult for this material.
en.wikipedia.org /wiki/Gallium_arsenide   (671 words)

  
 Solar Cells - Gallium Arsenide Solar Cells
Gallium arsenide (GaAs) is a compound semiconductor, a mixture of two elements, gallium (Ga) and arsenic (As).
One of the greatest advantages of gallium arsenide and its alloys as PV cell materials is the wide range of design options possible.
One way around this problem is to grow a relatively thick buffer layer of gallium arsenide between the silicon and the active GaAs cell; the buffer layer then absorbs many of the imperfections in the crystal structure.
www.sandia.gov /pv/docs/PVFSCGallium_Arsenide_Solar_Cells.htm   (1090 words)

  
 Stabilization of aluminum arsenide - Patent 4002505   (Site not responding. Last check: 2007-10-12)
Aluminum arsenide crystals, wherein gallium has been substituted for a minor portion of aluminum and which may be represented by the general formula Al.sub.1-x Ga.sub.x As wherein x has values in the range of 0.02 to 0.30, are annealed at a temperature of at least 700.degree.
The limitations in the application of aluminum arsenide are caused by difficulties in the preparation of high-purity single crystals, the reactivity of aluminum and the instability of crystals when exposed to moisture, such as, for example, contained in ambient air.
It is known that the binary compound gallium arsenide is chemically stable, while mixtures of gallium arsenide and aluminum arsenide, which form pseudo-binary or ternary compounds of aluminum, gallium and arsenic, are stable only at certain levels of their aluminum arsenide content.
www.freepatentsonline.com /4002505.html   (1461 words)

  
 LEOT Laser Tutorial - Applications in Photonics and Telecommunications - Module 3: Semiconductor Lasers   (Site not responding. Last check: 2007-10-12)
Draw and label the energy-level diagram of the gallium arsenide laser; use the diagram to explain the energy transfer during the lasing process.
Operate a gallium arsenide laser in the laboratory and measure its output characteristics.
The reflectivity at the interface between gallium arsenide and air is approximately 36%.
repairfaq.ece.drexel.edu /sam/CORD/leot/module3/module3.html   (5269 words)

  
 Aluminium gallium arsenide - Wikipedia, the free encyclopedia
Aluminium gallium arsenide (also Aluminum gallium arsenide) (Al
As) is a semiconductor material with very nearly the same lattice constant as GaAs, but a larger bandgap.
Extensive site on the physical properties of aluminium gallium arsenide
en.wikipedia.org /wiki/Aluminium_gallium_arsenide   (147 words)

  
 DHHS (NIOSH) Publication No. 88-100
Though these data demonstrate that exposure to gallium arsenide represents a source of arsenic exposure, the extent to which arsenic dissociates from gallium arsenide and the mechanism by which this dissociation occurs have not been determined in humans.
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.
Metabolism and excretion of orally and intraperitoneally administered gallium arsenide in the hamster.
www.cdc.gov /Niosh/88-100.html   (2265 words)

  
 Arsenide ore from Silver Centre, Ontario
Cobalt- nickel- arsenide ore of the Cobalt mining district
No silver minerals were noted in a brief examination, but the abundant arsenides are proof of a remarkably rich ore containing approximately 50 weight percent arsenic, 15 percent cobalt and 5 percent nickel.
Thin chlorite- calcite veinlets penetrate the host rock from the margins of the ore vein, which are lined by a thin selvage of two varieties of chlorite, ripidolite and penninite.
www.turnstone.ca /arsenide.htm   (975 words)

  
 News Release - Photovoltaic Power Source for Satellites   (Site not responding. Last check: 2007-10-12)
The addition of one or two percent nitrogen in gallium arsenide, a standard semiconductor material, dramatically alters the alloy's optical and electrical properties and causes "crazy physics" to occur, giving it characteristics suitable for satellite photovoltaics and laser applications, says Eric Jones, a Sandia physicist who has been working with the material for three years.
The arsenide nitride layer absorbs between deep red and infrared, and the germanium absorbs infrared and far infrared.
Without the addition of nitrogen, gallium arsenide's bandgap is too high to serve as a laser source.
www.sandia.gov /media/NewsRel/NR2000/InGaAsN.htm   (1288 words)

  
 Improved class of Gallium Arsenide transistors may lead to higher performance wireless, computer applications   (Site not responding. Last check: 2007-10-12)
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.
"After we further improve the gate oxide material, gallium arsenide MOSFET devices may be very attractive for various applications, such as cellular phones, wireless base stations and potentially microprocessors in computers," said researcher Ming-Hwei Hong of Bell Labs, which is the research and development arm of Lucent Technologies.
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.lucent.com /press/1298/981207.bla.html   (625 words)

  
 Wafer Technology: Gallium Arsenide
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)

  
 [No title]   (Site not responding. Last check: 2007-10-12)
Layer 12 is typically gallium arsenide (GaAs), but can be other materials, such as silicon (Si), indium phosphide (InP), lead telluride (PbTe), gallium nitride (GaN), Gallium phosphide (GaP), indium.
The method of claim 1, wherein a thickness of the second semiconductor layer is between 0.
The thermionic cooling device of claim 22, wherein the second semiconductor layer is the same material as the first semiconductor layer.
www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/33354.010719&ELEMENT_SET=DECL   (7213 words)

  
 Gallium Arsenide vs. Silicon   (Site not responding. Last check: 2007-10-12)
 arsenide lacks the silicon's ability to use its oxide form as an ideal insulator which can be used as a mask to protect the silicon.
 arsenide has poor thermal conductivity compared to silicon (the thermal conductivity of silicon is 2.75 times larger than that of gallium arsenide).
We are hearing that the new material of the future may not be arsenide, but rather silicon germanium.
www.ensc.sfu.ca /people/faculty/jones/ENSC100/Gamma/gallium.html   (561 words)

  
 Striking Effects of Nitrogen in Semiconductor Alloy Explained
On a substrate of gallium arsenide the researchers grew samples of gallium indium arsenide with varying small concentrations of nitrogen.
The samples, only 200 micrometers (millionths of a meter) square and less than five micrometers thick, were examined with modulated beams of light as the samples were squeezed in a diamond anvil cell to many thousands of times atmospheric pressure.
Meanwhile, gallium indium arsenide with nitrogen holds promise for other applications besides solar cells, such as in fiber optics, detectors, and light-emitting diodes.
www.lbl.gov /Science-Articles/Archive/nitrogen-solar-cell.html   (1277 words)

  
 gallium arsenide - a Whatis.com definition - see also: GaAs
Gallium arsenide (chemical formula GaAs) is a semiconductor compound used in some diodes, field-effect transistors (FETs), and integrated circuits (ICs).
The charge carriers, which are mostly electrons, move at high speed among the atoms.
Gallium arsenide is used in the manufacture of light-emitting diodes (LEDs), which are found in optical communications and control systems.
whatis.techtarget.com /definition/0,,sid9_gci213980,00.html   (191 words)

  
 Gallium Arsenide - as a Photovoltaic Material
Gallium arsenide's use in solar cells has been developing synergistically with its use in light-emitting diodes, lasers, and other optoelectronic devices.
Researchers are also exploring approaches to lowering the cost of GaAs devices, such as fabricating GaAs cells on cheaper substrates; growing GaAs cells on a removable, reusable GaAs substrate; and even making GaAs thin films similar to those of copper indium diselenide and cadmium telluride.
Current goals are to take this technology a step further by developing it as a concentrator technology and expanding it to include triple-junction devices.
www.azom.com /details.asp?ArticleID=1166   (609 words)

  
 Development of Gallium Arsenide Prescalers
To evaluate the capability of gallium arsenide integrated circuits, three different frequency divider chips have been designed at ESTEC and manufactured by Philips Microwave Limeil (F) using their prorietary ER07AD process.
Gallium arsenide gates are usually optimised for high speed, obtained at the expense of reduced gain and noise margin.
As proper extraction software was not available for back-annotating the parasitic elements in the layout, it was not possible to optimise the skew bet-ween phases of the two clocks, to which this type of circuit is very sensitive.
esapub.esrin.esa.it /pff/pffv5n2/hollrei.htm   (1304 words)

  
 MESFET with indium gallium arsenide etch stop - Patent 5283448
Semiconductor devices made of gallium arsenide (GaAs) are preferred over devices made of silicon for high frequency applications due to the higher mobility of carriers in gallium arsenide; however, gallium arsenide material and fabrication technology lag far behind that of silicon.
For example, gallium arsenide metal-semiconductor field effect transistor (MESFET) integrated circuits with more than a 1,000 gates have been fabricated (see, Toyoda et al, A 42ps 2K-Gate GaAs Gate Array, 1985 ISSCC Dig.Tech.Papers 206), but the precise control of device parameters such as threshold voltage for larger scale integration has not yet been achieved.
However, the fabrication of gallium arsenide bipolar (or heterojunction bipolar) transistors suitable for high speed applications, such as ECL, is complicated by the need for both a thin base and low base resistance.
www.freepatentsonline.com /5283448.html   (3936 words)

  
 Motorola mixes silicon, gallium arsenide for super-chips | The Register
The upshot is a part that's able to run at up to 40 times the speed of regular silicon circuitry, yet maintains the rugged nature of ordinary silicon chips.
Gallium arsenide chips have been around for some time, but they are delicate and hard to produce.
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   (480 words)

  
 News Release - VCSEL
The new 1.3-micron VCSEL is made mostly from stacks of layers of semiconductor materials common in shorter wavelength lasers -- aluminum gallium arsenide and gallium arsenide.
Esherick says laboratories around the world have been in a "horserace to be the first with the 1.3-micron VCSEL on gallium arsenide substrates." Cielo teamed with Sandia through a CRADA last year to research several compound semiconductor alloys in an effort to find the one that achieved the 1.3-micron goal.
VCSELs made of combinations of aluminum gallium arsenide and gallium arsenide have been used in the shorter wavelength window of 850 nanometers for local connections.
www.sandia.gov /media/NewsRel/NR2000/laser.htm   (840 words)

  
 Do you know your arsenide from your elbow?   (Site not responding. Last check: 2007-10-12)
Four compounds account for most of the current demand for these semiconductors today: Gallium arsenide, the largest at almost three-quarters of the total, followed by gallium nitride at approximately 13%, silicon germanium at 12%, and indium phosphide at 1%.
Gallium nitride emits light in the blue region of the spectrum and is an ideal light source for compact hard disk drives.
Applications exist today that did were simply not around when gallium arsenide was first developed, especially in digital display appliances and mobile communications.
www.theinquirer.net /10050207.htm   (549 words)

  
 News Item: Motorola Creates New Gallium Arsenide and Silicon Semiconductors
Motorola Inc. announced today that Motorola Labs scientists are the first to successfully combine the best properties of workhorse silicon technology with the speed and optical capabilities of high-performance compound semiconductors that are known as the III-V materials.
The technology enables very thin layers of so-called III-V semiconductor materials (which include gallium arsenide, indium phosphide, gallium nitride and other high performance/light-emitting compounds) to be grown on a silicon substrate.
Until now, the industry has been dependent on costly gallium arsenide and indium phosphide wafers for optical and high performance applications.
www.azom.com /details.asp?ArticleID=861   (879 words)

  
 Gallium Arsenide - GaAs   (Site not responding. Last check: 2007-10-12)
Gallium arsenide has many uses including being used in some diodes, field-effect transistors (FETs), and integrated circuits (ICs).
GaAs devices generate less noise than most other types of semiconductor components and, as a result, are useful in weak-signal amplification applications.
Researchers are also exploring approaches to lowering the cost of Gallium Arsenide devices, such as fabricating GaAs cells on cheaper substrates; growing GaAs cells on a removable, reusable GaAs substrate; and even making GaAs thin films similar to those of copper indium diselenide and cadmium telluride.
www.logitech.uk.com /gallium_arsenide.asp   (290 words)

  
 Nickeline (Nickel Arsenide)
The miners in Germany who first saw the copper-red metallic mineral were convinced the mineral was a rich ore of copper.
Instead, try as they might, no copper was to be produced from the nickel arsenide.
The metal that was produced from the mineral was found to be useful and valuable and it is from this unflattering term that the metal received its name, nickel (Ni).
mineral.galleries.com /minerals/sulfides/nickelin/nickelin.htm   (676 words)

  
 Gallium
AXT specializes in growing crystals of gallium arsenide, a compound semiconductor whose properties have special applications in fiber optics and solar cells...
The laser chip uses aluminum gallium indium arsenide in the active layer, enabling a greater electron containment effect and operations at higher temperatures...
The materials may be silicon, germanium, silicon-germanium alloys (eg strained silicon), gallium arsenide, aluminum gallium arsenide, gallium nitride, indium...
carcinogens.cancer-help.org /Gallium.html   (7805 words)

  
 Bell Labs discovery may lead to improved class of gallium arsenide transistors and longer talk times on cellular phones   (Site not responding. Last check: 2007-10-12)
The researchers have grown a single crystal of gadolinium oxide on a gallium arsenide semiconductor.
For this reason, the channel is known as the transistor's active region, and it must have a smooth, defect-free interface with the gate oxide layer to operate properly.
Previously, Bell Labs researchers developed functional gallium arsenide MOSFETs with a gate oxide that was a mixture of gallium oxide and gadolinium oxide.
www.lucent.com /press/0399/990319.bla.html   (585 words)

  
 Cryogenic Sensors - Gallium Arsenide Diode Thermometer - Model GA-300   (Site not responding. Last check: 2007-10-12)
Our Gallium Arsenide temperature sensors are available in both two and four lead configurations.
The standard calibration range for the GA-300 Gallium Arsenide Diode sensor is 1.5 K to 300 K. Data are supplied over this range at temperature points and increments according to the following table.
For best results be sure to thermally anchor both the sensor and leads to the material, or sample, whose temperature is to be measured.
www.scientificinstruments.com /sensors/ga-300.htm   (400 words)

  
 OhioLINK ETD: Yang, Ming-Chang
Gallium arsenide films have been electrodeposited from both alkaline and acid aqueous electrolytes.
Compared to other conventional methods of preparing gallium arsenide films, electrodeposition from aqueous solution has the advantages of low operating and equipment costs, relatively easy control of film properties and no toxic volatile raw material.
Mixtures of the deposited elements of gallium and arsenic also became crystalline gallium arsenide after annealing.
rave.ohiolink.edu /etdc/view?acc_num=case1059135267   (215 words)

  
 Sensors Unlimited, Inc. - What is InGaAs?
InGaAs, or indium gallium arsenide, is an alloy of gallium arsenide and indium arsenide.
In a more general sense, it belongs to the InGaAsP quaternary system that consists of alloys of indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), and gallium phosphide (GaP).
As gallium and indium belong to Group III of the Periodic Table, and arsenic and phosphorous belong to Group V, these binary materials and their alloys are all III-V compound semiconductors.
www.sensorsinc.com /GaAs.html   (694 words)

  
 NCSR - Aluminum Arsenide
AlAs in general is considered most useful when it is alloyed with Gallium Arsenide to form optical devices with the desired band structure, or for the formation of heterojunctions in devices.
Aluminum Arsenide has an indirect band gap which changes to direct when alloyed with Ga (AlGaAs) with about 38% or less Aluminum (Ref.
An interesting note is the lattice constant of GaAs and AlAs are very close, enabling abrupt changes in the ratio of Ga and Al without large amounts of strain.
www.onr.navy.mil /sci_tech/information/312_electronics/ncsr/materials/alas.asp?css=printer   (164 words)

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