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|Section2= |Section3= |Section7= }} Gallium arsenide (GaAs) is a compound of the elements gallium and arsenic. It is a III-V direct bandgap semiconductor with a zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monolithic microwave integrated circuits, infrared light-emitting diodes, laser diodes, solar cells and optical windows.〔 GaAs is often used as a substrate material for the epitaxial growth of other III-V semiconductors including: Indium gallium arsenide, aluminum gallium arsenide and others. ==Preparation and chemistry== In the compound, gallium has a +3 oxidation state. Gallium arsenide single crystals can be prepared by three industrial processes: *The vertical gradient freeze (VGF) process (most GaAs wafers are produced using this process). *Crystal growth using a horizontal zone furnace in the Bridgman-Stockbarger technique, in which gallium and arsenic vapors react, and free molecules deposit on a seed crystal at the cooler end of the furnace. *Liquid encapsulated Czochralski (LEC) growth is used for producing high-purity single crystals that can exhibit semi-insulating characteristics (see below). Alternative methods for producing films of GaAs include:〔 *VPE reaction of gaseous gallium metal and arsenic trichloride: 2 Ga + 2 → 2 GaAs + 3 *MOCVD reaction of trimethylgallium and arsine: + → GaAs + 3 *Molecular beam epitaxy (MBE) of gallium and arsenic: 4 Ga + → 4 GaAs or 2 Ga + → 2 GaAs Oxidation of GaAs occurs in air and degrades performance of the semiconductor. The surface can be passivated by depositing a cubic gallium(II) sulfide layer using a tert-butyl gallium sulfide compound such as (.〔"Chemical vapor deposition from single organometallic precursors" A. R. Barron, M. B. Power, A. N. MacInnes, A. F.Hepp, P. P. Jenkins (1994)〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gallium arsenide」の詳細全文を読む スポンサード リンク
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