Semiconductors indium compounds

Intermetallic compounds with gallium are used as semiconductors. Indium is used to coat other metals to protect against corrosion, especially in engine bearings it is also a constituent of low-metal alloys used in safety sprinklers. The toxicity of thallium compounds has limited the use of the metal, but it does find use as a constituent of high-endurance alloys for bearings. 

The supplanting of germanium-based semiconductor devices by shicon devices has almost eliminated the use of indium in the related ahoy junction (see Semiconductors). Indium, however, is finding increased use in III—V compound semiconductors such as indium phosphide [22398-80-7] for laser diodes used in fiber optic communication systems (see Electronic materials Fiber optics Light generation). Other important indium-containing semiconductors include indium arsenide [1303-11-3] indium antimonide [1312-41 -0] and copper—indium—diselenide [12018-95-0]. 

Indium metal dust, particles, and vapors are toxic if ingested or inhaled, as are most of the compounds of indium. This requires the semiconductor and electronics industries that use indium compounds to provide protection for their workers. 

The growing use of trialkylgallium and -indium compounds in the synthesis of semiconductors has led to the issuance of patented methods for their preparation from metal-magnesium alloys and alkyl halides (68-71). Other such preparations are likely to appear as the need for alkylmetal compounds increases. 

Indium is a soft malleable, silvery white metal. Due to its low friction properties, it is used in bearing alloys. Certain indium compounds have unique semiconductor properties. Films of ITO, indium-tin oxide (80% In Oj), are transparent to visible light but not for infrared light. In addition they have good electrical conductivity. The electrical conductivity of the thin coating is utilized on windshields for railway locomotives and airplanes to make it possible to warm them up with electric current for defogging. 

Mercury Telluride. Compounds of mercury with tellurium have gained importance as semiconductors with appHcations in infrared detection (9) and solar cells (10). The ratio of the components is varied, and other elements such as cadmium, zinc, and indium are added to modify the electronic characteristics. 

Semiconductors. Phosphine is commonly used in the electronics industry as an -type dopant for siUcon semiconductors (6), and to a lesser extent for the preparation of gaUium—indium—phosphide devices (7). For these end uses, high purity, electronic-grade phosphine is required normally >99.999% pure. The main impurities that occur in phosphine manufactured by the acid process are nitrogen [7727-37-9] hydrogen [1333-74-0] arsine [7784-42-17, carbon dioxide [124-38-9], oxygen [7782-44-7], methane [74-82-8], carbon monoxide [630-08-0], and water [7732-42-1]. Phosphine is purified by distillation under pressure to reduce the level of these compounds to <1 ppm by volume. The final product is sold as CYPURE (Cytec Canada Inc.) phosphine. 

Metallic Antimonides. Numerous binary compounds of antimony with metallic elements are known. The most important of these are indium antimonide [1312-41 -0] InSb, gallium antimonide [12064-03-8] GaSb, and aluminum antimonide [25152-52-7] AlSb, which find extensive use as semiconductors. The alkali metal antimonides, such as lithium antimonide [12057-30-6] and sodium antimonide [12058-86-5] do not consist of simple ions. Rather, there is appreciable covalent bonding between the alkali metal and the Sb as well as between pairs of Na atoms. These compounds are useful for the preparation of organoantimony compounds, such as trimethylstibine [594-10-5] (CH2)2Sb, by reaction with an organohalogen compound. 

Extensive structural, optical, and electronic studies on the chalcopyrite semiconductors have been stimulated by the promising photovoltaic and photoelectrochem-ical properties of the copper-indium diselenide, CuInSe2, having a direct gap of about 1.0 eV, viz. close to optimal for terrestrial photovoltaics, and a high absorption coefficient which exceeds 10 cm . The physical properties of this and the other compounds of the family can be modulated to some extent by a slight deviation from stoichiometry. Thus, both anion and cation deficiencies may be tolerated, inducing, respectively, n- and p-type conductivities a p-type behavior would associate to either selenium excess or copper deficiency. 

Indium and gallium coordination compounds containing phosphine ligands have recently aroused interest for their widespread application as intermediates in the preparation of the Group 13 - Group 14 semiconductors [4], Since the early reports about compounds with transition metal-indium bonds [51, relatively little research has been reported in this field. However there is a growing interest in the coordination chemistry and structural features of heterometallic indium [6] and gallium complexes [7] which are also attractive as potential precursors of new materials with particular properties. 

Indiums low melting point is the major factor in determining its commercial importance. This factor makes it ideal for soldering the lead wires to semiconductors and transistors in the electronics industry. The compounds of indium arsenide, indium antimonide, and indium phosphide are used to construct semiconductors that have specialized functions in the electronics industry. 

There are many other compounds of indium, most of which are useful in the electronics and semiconductor industries. Some other examples are InP, Inj(SO )j, In Te, and InSb. 

Indium combines with several metals, such as sodium, potassium, magnesium, iron, palladium, platinum, lanthanium and cerium, forming semiconductor-type intermetallic compounds. 

In our opinion the electrodeposition of selenium is quite promising for a variety of applications. For example, the possibility to deposit grey selenium, indium, and copper in one ionic liquid at variable temperatures might be regarded as the first step in making selenium-containing compound semiconductors like CIS by electrochemical means. 

The mobility and resistivity data of single crystalline zinc oxide samples (measured at room temperature) from different authors, which were reported from 1957 to 2005, are displayed in Fig. 2.6 as a function of the carrier concentration (part of these data were taken from [67]). Undoped ZnO crystals exhibit carrier concentrations as low as 1015 cm-3, while indium-doped crystals reach carrier concentrations up to 7 x 1019cm-3. The mobility data show a large scattering between carrier concentrations of 1017 to 5 x 1018cm-3. This is caused by the fact that zinc oxide is a compound semiconductor that is not as well developed as other semiconducting compounds. For instance, only... 

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