Gallium arsenide Chemical Properties
- Melting point:1238°C
- Density 5.31 g/mL at 25 °C(lit.)
- refractive index 3.57
- form pieces
- Specific Gravity5.31
- color Dark gray
- Resistivity≥1E7 Ω-cm
- Water Solubility Soluble in hydrochloric acid. Insoluble in water, ethanol, methanol and acetone.
- Merck 14,4347
- CAS DataBase Reference1303-00-0(CAS DataBase Reference)
- EPA Substance Registry SystemGallium arsenide (1303-00-0)
Gallium arsenide Usage And Synthesis
- Chemical PropertiesGallium arsenide contains 48.2% gallium and 51.8% arsenic and is considered an intermetallic compound. It occurs as cubic crystals with a dark gray metallic sheen. Gallium arsenide is electroluminescent in infrared light. Gallium arsenide readily reacts with oxygen in air, forming a mixture of oxides of gallium and arsenic on the crystal surface. Gallium arsenide presents the following properties: hardness, 4.5; thermal expansion coefficient, 5.9×106; thermal conductivity, 0.52Wunits; specific heat, 0.086 cal/g/ ℃; intrinsic electron concentration, 107; energy gap at room temperature, 1.38 eV; electron mobility, 8800 cm2/V/s; effective mass for electrons, 0.06m0; lattice constant,5.6–54 AO; dielectric constant, 11.1; intrinsic resistivity at 300K＝3.7×108Ωcm; electron lattice mobility at 300K＝ 10,000 cm2/V/s; intrinsic charge density at 300K＝1.4 106 cm-3; electron diffusion constant at 300K＝310 cm2/s; and hole diffusion constant＝11.5 cm2/s.
Garlic odor when moistened. Finely divided gallium arsenide can react vigorously with steam, energetic acids, and oxidizers to evolve arsine gas, and can release arsenic fumes when heated to decomposition. The molten form attacks quartz.
- Physical propertiesGray cubic crystal; density 5.316 g/cm3; melts at 1,227°C; hardness 4.5 Mohs; lattice constant 5.653?; dielectric constant 11.1; resistivity (intrinsic) at 27°C, 3.7x108 ohm-cm.
- UsesIn semiconductor applications (transistors, solar cells, lasers).Gallium arsenide is among the most widely used intermetallic semiconductor components (Harrison, 1986; McIntyr and Sherin, 1989). Gallium arsenide is also incorporated into light-emitting diodes and photovoltaic cells, while gallium alloys are used for dental amalgam as a low toxicity replacement for mercury.
- UsesGallium arsenide, GaAs, is considered a possible substitute for silicon substrates, based on its potential for high speed applications where it can operate at high (1.9 GHz) frequencies using low power consumptions and high sensitivity. One reason that GaAs technology has not fulfilled its promise is that silicon technology has dramatically improved in the interim, particularly with improvements in speed, and has reduced the cost-effectiveness of pursuing GaAs development
- UsesGallium arsenide is electroluminscent in infrared light and is used for telephone equipment, lasers, solar cell, and other electronic devices.
- PreparationGallium arsenide is prepared by passing a mixture of arsenic vapor and hydrogen over gallium(III) oxide heated at 600°C: Ga2O3 + 2As + 3H2 2GaAs + 3H2OThe molten material attacks quartz. Therefore, quartz boats coated with carbon by pyrolytic decomposition of methane should be used in refining the compound to obtain high purity material. Gallium arsenide is produced in polycrystalline form as high purity, single crystals for electronic applications. It is produced as ingots or alloys, combined with indium arsenide or gallium phosphide, for semiconductor applications.
- General DescriptionDark gray crystals with a metallic greenish-blue sheen or gray powder. Melting point 85.6°F (29.78°C).
- Air & Water ReactionsStable in dry air. Tarnishes in moist air. Insoluble in water.
- Reactivity ProfileGALLIUM ARSENIDE can react with steam, acids and acid fumes. Reacts with bases with evolution of hydrogen. Attacked by cold concentrated hydrochloric acid. Readily attacked by the halogens. The molten form attacks quartz.
- HazardToxic metal. Questionable carcinogen
- Fire HazardFlash point data for GALLIUM ARSENIDE are not available; however, GALLIUM ARSENIDE is probably combustible.
- Safety ProfileConfirmed carcinogen. Mddly toxic by intraperitoneal route. Most arsenic compounds are poisons. Can react with steam, acids, and acid fumes to evolve the deadly poisonous arsine. Molten gallium arsenide attacks quartz. When heated to decomposition it emits very toxic fumes of As. See also ARSENIC COMPOUNDS and GALLIUM COMPOUNDS.
Gallium is antineoplastic in several human and murine cancer cell lines and in some in vivo cancers. It has been used experimentally in patients in the treatment of lymphatic malignancies (including multiple myelomas) and for urothelial malignancies. However, the dissociation of gallium arsenide into gallium and arsenic is a factor to take into account. A considerable number of studies have evaluated the carcinogenic potential of arsenic and various arsenic compounds.
- Gallium Zinc sulfide TRIS(2,2,6,6-TETRAMETHYL-3,5-HEPTANEDIONATO)GALLIUM(III) GALLIUM(III) SULFATE HYDRATE TRIMETHYLGALLIUM Zinc selenide ZINC TELLURIDE Cadmium sulfide CADMIUM SELENIDE CADMIUM TELLURIDE INDIUM PHOSPHIDE GALLIUM PHOSPHIDE Gallium(III) oxide Gallium arsenide Aluminum gallium arsenide Gallium arsenide phosphide ARSINE ARSENIC PENTOXIDE
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