90-444: Indium gallium nitride ( InGaN , In x Ga 1− x N ) is a semiconductor material made of a mix of gallium nitride (GaN) and indium nitride (InN). It is a ternary group III / group V direct bandgap semiconductor . Its bandgap can be tuned by varying the amount of indium in the alloy. In x Ga 1−x N has a direct bandgap span from the infrared (0.69 eV) for InN to the ultraviolet (3.4 eV) of GaN. The ratio of In/Ga
180-428: A s {\displaystyle a_{s}} are the lattice constants of the film and the substrate. The film and substrate could have similar lattice spacings but also different thermal expansion coefficients. If a film is grown at a high temperature, it can experience large strains upon cooling to room temperature. In reality, ε < 9 % {\displaystyle \varepsilon <9\%}
270-561: A boride , silicide , or carbide , and the hydride InH 3 has at best a transitory existence in ethereal solutions at low temperatures, being unstable enough to spontaneously polymerize without coordination. Indium is rather basic in aqueous solution, showing only slight amphoteric characteristics, and unlike its lighter homologs aluminium and gallium, it is insoluble in aqueous alkaline solutions. Indium has 39 known isotopes , ranging in mass number from 97 to 135. Only two isotopes occur naturally as primordial nuclides : indium-113,
360-436: A by-product during smelting. While the enrichment of indium in these deposits is high relative to its crustal abundance, it is insufficient, at current prices, to support extraction of indium as the main product. Different estimates exist of the amounts of indium contained within the ores of other metals. However, these amounts are not extractable without mining of the host materials (see Production and availability). Thus,
450-497: A by-product during the processing of the ores of other metals, chiefly from sphalerite and other zinc sulfide ores . Indium has no biological role and its compounds are toxic when inhaled or injected into the bloodstream, although they are poorly absorbed following ingestion. The name comes from the Latin word indicum meaning violet or indigo . Indium is a shiny silvery-white, highly ductile post-transition metal with
540-447: A recommended exposure limit (REL) of 0.1 mg/m over an eight-hour workday. Epitaxy Epitaxy (prefix epi- means "on top of”) refers to a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline seed layer. The deposited crystalline film is called an epitaxial film or epitaxial layer. The relative orientation(s) of
630-447: A size effect in bending and indentation, associated to a length-scale of order 50–100 μm, significantly large when compared with other metals. Indium has 49 electrons, with an electronic configuration of [ Kr ]4d 5s 5p . In compounds, indium most commonly donates the three outermost electrons to become indium(III), In . In some cases, the pair of 5s-electrons are not donated, resulting in indium(I), In . The stabilization of
720-512: A transparent conductive coating on glass substrates in electroluminescent panels. Indium tin oxide is used as a light filter in low-pressure sodium-vapor lamps . The infrared radiation is reflected back into the lamp, which increases the temperature within the tube and improves the performance of the lamp. Indium has many semiconductor -related applications. Some indium compounds, such as indium antimonide and indium phosphide , are semiconductors with useful properties: one precursor
810-494: A = 325 pm , c = 495 pm): this is a slightly distorted face-centered cubic structure, where each indium atom has four neighbours at 324 pm distance and eight neighbours slightly further (336 pm). Indium has greater solubility in liquid mercury than any other metal (more than 50 mass percent of indium at 0 °C). Indium displays a ductile viscoplastic response, found to be size-independent in tension and compression. However it does have
900-437: A bright luster . It is so soft ( Mohs hardness 1.2) that it can be cut with a knife and leaves a visible line like a pencil when rubbed on paper. It is a member of group 13 on the periodic table and its properties are mostly intermediate between its vertical neighbors gallium and thallium . As with tin , a high-pitched cry is heard when indium is bent – a crackling sound due to crystal twinning . Like gallium, indium
990-431: A case, the seed layer consists of grains with different in-plane textures. The epitaxial overlayer then creates specific textures along each grain of the seed layer, due to lattice matching. This kind of epitaxial growth doesn't involve single-crystal films. Epitaxy is used in silicon -based manufacturing processes for bipolar junction transistors (BJTs) and modern complementary metal–oxide–semiconductors (CMOS), but it
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#17328489475841080-417: A corner of a cube). The hematite structure is based on close-packed oxygen anions stacked in an AB-AB sequence, which results in a crystal with hexagonal symmetry. If the cations were small enough to fit into a truly close-packed structure of oxygen anions then the spacing between the nearest neighbour oxygen sites would be the same for both species. The radius of the oxygen ion, however, is only 1.36 Å and
1170-533: A crystalline film grows on a crystalline substrate or film of a different material. This technology is often used to grow crystalline films of materials for which crystals cannot otherwise be obtained and to fabricate integrated crystalline layers of different materials. Examples include silicon on sapphire , gallium nitride (GaN) on sapphire , aluminium gallium indium phosphide (AlGaInP) on gallium arsenide (GaAs) or diamond or iridium , and graphene on hexagonal boron nitride (hBN). Heteroepitaxy occurs when
1260-423: A film of different composition and/or crystalline films grown on a substrate. In this case, the amount of strain in the film is determined by the lattice mismatch Ԑ: ε = a f − a s a f {\displaystyle \varepsilon ={\frac {a_{f}-a_{s}}{a_{f}}}} Where a f {\displaystyle a_{f}} and
1350-412: A high supersaturation regime, away from thermodynamic equilibrium. In that case, the epitaxial growth is governed by adatom kinetics rather than thermodynamics, and 2D step-flow growth becomes dominant. Homoepitaxial growth of semiconductor thin films are generally done by chemical or physical vapor deposition methods that deliver the precursors to the substrate in gaseous state. For example, silicon
1440-447: A larger emitting surface, better efficiency and greater light emission compared to planar LEDs . The toxicology of InGaN has not been fully investigated. The dust is an irritant to skin, eyes and lungs. The environment, health and safety aspects of indium gallium nitride sources (such as trimethylindium , trimethylgallium and ammonia ) and industrial hygiene monitoring studies of standard MOVPE sources have been reported recently in
1530-438: A lower bandgap than the surrounding material and create regions of reduced potential energy for charge carriers. Electron-hole pairs are trapped there and recombine with emission of light, instead of diffusing to crystal defects where the recombination is non-radiative. Also, self-consistent computer simulations have shown that radiative recombination is focused where regions are rich of indium. The emitted wavelength, dependent on
1620-462: A minor dependence on small variations of device dimensions. Studies based on device simulation have shown that it could be possible to increase InGaN/GaN LED efficiency using band gap engineering, especially for green LEDs. The ability to perform bandgap engineering with InGaN over a range that provides a good spectral match to sunlight, makes InGaN suitable for solar photovoltaic cells . It is possible to grow multiple layers with different bandgaps, as
1710-509: A new element was present in the minerals. They named the element indium, from the indigo color seen in its spectrum, after the Latin indicum , meaning 'of India '. Richter went on to isolate the metal in 1864. An ingot of 0.5 kg (1.1 lb) was presented at the World Fair 1867. Reich and Richter later fell out when the latter claimed to be the sole discoverer. Indium is created by
1800-429: A review. Indium Indium is a chemical element ; it has symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium , and its properties are largely intermediate between the two. It was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods and named for
1890-613: A type of second-generation thin-film solar cell . Indium is used in PNP bipolar junction transistors with germanium : when soldered at low temperature, indium does not stress the germanium. Indium wire is used as a vacuum seal and a thermal conductor in cryogenics and ultra-high-vacuum applications, in such manufacturing applications as gaskets that deform to fill gaps. Owing to its great plasticity and adhesion to metals, Indium sheets are sometimes used for cold-soldering in microwave circuits and waveguide joints, where direct soldering
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#17328489475841980-408: A valued property of stabilizing non-ferrous metals , and that became the first significant use for the element. The first large-scale application for indium was coating bearings in high-performance aircraft engines during World War II , to protect against damage and corrosion ; this is no longer a major use of the element. New uses were found in fusible alloys , solders , and electronics . In
2070-510: Is LCD production. Demand rose rapidly from the late 1990s to 2010 with the popularity of LCD computer monitors and television sets, which now account for 50% of indium consumption. Increased manufacturing efficiency and recycling (especially in Japan) maintain a balance between demand and supply. According to the UNEP , indium's end-of-life recycling rate is less than 1%. In 1924, indium was found to have
2160-706: Is albite NaAlSi 3 O 8 on microcline KAlSi 3 O 8 . Both these minerals are triclinic , with space group 1 , and with similar unit cell parameters, a = 8.16 Å, b = 12.87 Å, c = 7.11 Å, α = 93.45°, β = 116.4°, γ = 90.28° for albite and a = 8.5784 Å, b = 12.96 Å, c = 7.2112 Å, α = 90.3°, β = 116.05°, γ = 89° for microcline. Minerals that have the same composition but different structures ( polymorphic minerals ) may also have epitaxic relations. Examples are pyrite and marcasite , both FeS 2 , and sphalerite and wurtzite , both ZnS. Some pairs of minerals that are not related structurally or compositionally may also exhibit epitaxy. A common example
2250-418: Is rutile TiO 2 on hematite Fe 2 O 3 . Rutile is tetragonal and hematite is trigonal , but there are directions of similar spacing between the atoms in the (100) plane of rutile (perpendicular to the a axis ) and the (001) plane of hematite (perpendicular to the c axis). In epitaxy these directions tend to line up with each other, resulting in the axis of the rutile overgrowth being parallel to
2340-413: Is a moderately strong oxidizing agent , indium(III) is not, and many indium(I) compounds are powerful reducing agents . While the energy required to include the s-electrons in chemical bonding is lowest for indium among the group 13 metals, bond energies decrease down the group so that by indium, the energy released in forming two additional bonds and attaining the +3 state is not always enough to outweigh
2430-454: Is a process in which the heteroepitaxial film is growing vertically and laterally simultaneously. In 2D crystal heterostructure, graphene nanoribbons embedded in hexagonal boron nitride give an example of pendeo-epitaxy. Grain-to-grain epitaxy involves epitaxial growth between the grains of a multicrystalline epitaxial and seed layer. This can usually occur when the seed layer only has an out-of-plane texture but no in-plane texture. In such
2520-402: Is able to wet glass. Like both, indium has a low melting point , 156.60 °C (313.88 °F); higher than its lighter homologue, gallium, but lower than its heavier homologue, thallium, and lower than tin. The boiling point is 2072 °C (3762 °F), higher than that of thallium, but lower than gallium, conversely to the general trend of melting points, but similarly to the trends down
2610-460: Is about two weeks in humans. It is also tagged to growth hormone analogues like octreotide to find growth hormone receptors in neuroendocrine tumors . Indium has no metabolic role in any organism. In a similar way to aluminium salts, indium(III) ions can be toxic to the kidney when given by injection. Indium tin oxide and indium phosphide harm the pulmonary and immune systems, predominantly through ionic indium, though hydrated indium oxide
2700-450: Is also considered to be a type of solid phase epitaxy. The impurity segregation and redistribution at the growing crystal-amorphous layer interface during this process is used to incorporate low-solubility dopants in metals and silicon. An epitaxial layer can be doped during deposition by adding impurities to the source gas, such as arsine , phosphine , or diborane . Dopants in the source gas, liberated by evaporation or wet etching of
2790-423: Is commonly used to create so-called bandgap systems thanks to the additional energy caused by de deformation. A very popular system with great potential for microelectronic applications is that of Si–Ge. Heterotopotaxy is a process similar to heteroepitaxy except that thin-film growth is not limited to two-dimensional growth; the substrate is similar only in structure to the thin-film material. Pendeo-epitaxy
Indium gallium nitride - Misplaced Pages Continue
2880-456: Is complicated. Indium is an ingredient in the gallium–indium–tin alloy galinstan , which is liquid at room temperature and replaces mercury in some thermometers . Other alloys of indium with bismuth , cadmium , lead , and tin , which have higher but still low melting points (between 50 and 100 °C), are used in fire sprinkler systems and heat regulators. Indium is one of many substitutes for mercury in alkaline batteries to prevent
2970-618: Is done by electrolysis . The exact process varies with the mode of operation of the smelter. Its by-product status means that indium production is constrained by the amount of sulfidic zinc (and copper) ores extracted each year. Therefore, its availability needs to be discussed in terms of supply potential. The supply potential of a by-product is defined as that amount which is economically extractable from its host materials per year under current market conditions (i.e. technology and price). Reserves and resources are not relevant for by-products, since they cannot be extracted independently from
3060-417: Is heated. In 2 O 3 adopts a structure like alumina and is amphoteric, that is able to react with both acids and bases. Indium reacts with water to reproduce soluble indium(III) hydroxide , which is also amphoteric; with alkalis to produce indates(III); and with acids to produce indium(III) salts: The analogous sesqui-chalcogenides with sulfur , selenium , and tellurium are also known. Indium forms
3150-405: Is in the semiconductor industry, where semiconductor films are grown epitaxially on semiconductor substrate wafers. For the case of epitaxial growth of a planar film atop a substrate wafer, the epitaxial film's lattice will have a specific orientation relative to the substrate wafer's crystalline lattice, such as the [001] Miller index of the film aligning with the [001] index of the substrate. In
3240-546: Is more than forty times as toxic when injected, measured by the quantity of indium introduced. People can be exposed to indium in the workplace by inhalation, ingestion, skin contact, and eye contact. Indium lung is a lung disease characterized by pulmonary alveolar proteinosis and pulmonary fibrosis, first described by Japanese researchers in 2003. As of 2010 , 10 cases had been described, though more than 100 indium workers had documented respiratory abnormalities. The National Institute for Occupational Safety and Health has set
3330-485: Is most commonly deposited from silicon tetrachloride (or germanium tetrachloride ) and hydrogen at approximately 1200 to 1250 °C: where (g) and (s) represent gas and solid phases, respectively. This reaction is reversible, and the growth rate depends strongly upon the proportion of the two source gases. Growth rates above 2 micrometres per minute produce polycrystalline silicon, and negative growth rates ( etching ) may occur if too much hydrogen chloride byproduct
3420-416: Is necessary for obtaining epitaxy. If ε {\displaystyle \varepsilon } is larger than that, the film experiences a volumetric strain that builds with each layer until a critical thickness. With increased thickness, the elastic strain in the film is relieved by the formation of dislocations, which can become scattering centers that damage the quality of the structure. Heteroepitaxy
3510-476: Is often used to grow a more pure film than the substrate and to fabricate layers with different doping levels. In academic literature, homoepitaxy is often abbreviated to "homoepi". Homotopotaxy is a process similar to homoepitaxy except that the thin-film growth is not limited to two-dimensional growth. Here the substrate is the thin-film material. Heteroepitaxy is a kind of epitaxy performed with materials that are different from each other. In heteroepitaxy,
3600-430: Is particularly important for compound semiconductors such as gallium arsenide . Manufacturing issues include control of the amount and uniformity of the deposition's resistivity and thickness, the cleanliness and purity of the surface and the chamber atmosphere, the prevention of the typically much more highly doped substrate wafer's diffusion of dopant to the new layers, imperfections of the growth process, and protecting
3690-539: Is present. (Hydrogen chloride may be intentionally added to etch the wafer.) An additional etching reaction competes with the deposition reaction: Silicon VPE may also use silane , dichlorosilane , and trichlorosilane source gases. For instance, the silane reaction occurs at 650 °C in this way: VPE is sometimes classified by the chemistry of the source gases, such as hydride VPE (HVPE) and metalorganic VPE (MOVPE or MOCVD). The reaction chamber where this process takes place may be heated by lamps located outside
Indium gallium nitride - Misplaced Pages Continue
3780-572: Is the 68th most abundant element in Earth's crust at approximately 50 ppb . This is similar to the crustal abundance of silver , bismuth and mercury . It very rarely forms its own minerals, or occurs in elemental form. Fewer than 10 indium minerals such as roquesite (CuInS 2 ) are known, and none occur at sufficient concentrations for economic extraction. Instead, indium is usually a trace constituent of more common ore minerals, such as sphalerite and chalcopyrite . From these, it can be extracted as
3870-446: Is the growth of an overlayer crystal with one well-defined orientation with respect to the substrate crystal, is preferred. Epitaxy can also play an important role in the growth of superlattice structures. The term epitaxy comes from the Greek roots epi (ἐπί), meaning "above", and taxis (τάξις), meaning "an ordered manner". One of the main commercial applications of epitaxial growth
3960-481: Is theoretically predicted that spinodal decomposition of indium nitride should occur for compositions between 15% and 85%, leading to In-rich and Ga-rich InGaN regions or clusters. However, only a weak phase segregation has been observed in experimental local structure studies. Other experimental results using cathodoluminescence and photoluminescence excitation on low In-content InGaN multi- quantum wells have demonstrated that providing correct material parameters of
4050-407: Is used in nuclear medicine tests, as a radiotracer to follow the movement of labeled proteins and white blood cells to diagnose different types of infection. Indium compounds are mostly not absorbed upon ingestion and are only moderately absorbed on inhalation; they tend to be stored temporarily in the muscles , skin , and bones before being excreted, and the biological half-life of indium
4140-509: Is usually trimethylindium (TMI), which is also used as the semiconductor dopant in II–VI compound semiconductors . InAs and InSb are used for low-temperature transistors and InP for high-temperature transistors. The compound semiconductors InGaN and InGaP are used in light-emitting diodes (LEDs) and laser diodes. Indium is used in photovoltaics as the semiconductor copper indium gallium selenide (CIGS), also called CIGS solar cells ,
4230-475: Is usually between 0.02/0.98 and 0.3/0.7. Indium gallium nitride is the light-emitting layer in modern blue and green LEDs and often grown on a GaN buffer on a transparent substrate as, e.g. sapphire or silicon carbide . It has a high heat capacity and its sensitivity to ionizing radiation is low (like other group III nitrides ), making it also a potentially suitable material for solar photovoltaic devices, specifically for arrays for satellites . It
4320-401: The halides In 2 X 4 and [In 2 X 6 ] , and various subchalcogenides such as In 4 Se 3 . Several other compounds are known to combine indium(I) and indium(III), such as In 6 (In Cl 6 )Cl 3 , In 5 (In Br 4 ) 2 (In Br 6 ), and In In Br 4 . Organoindium compounds feature In–C bonds. Most are In(III) derivatives, but cyclopentadienylindium(I) is an exception. It
4410-401: The indigo blue line in its spectrum. Indium is a technology-critical element used primarily in the production of flat-panel displays as indium tin oxide (ITO), a transparent and conductive coating applied to glass. Indium is also used in the semiconductor industry , in low-melting-point metal alloys such as solders and soft-metal high-vacuum seals. It is produced exclusively as
4500-416: The monovalent state is attributed to the inert pair effect , in which relativistic effects stabilize the 5s-orbital, observed in heavier elements. Thallium (indium's heavier homolog ) shows an even stronger effect, causing oxidation to thallium(I) to be more probable than to thallium(III), whereas gallium (indium's lighter homolog) commonly shows only the +3 oxidation state. Thus, although thallium(III)
4590-435: The zinc from corroding and releasing hydrogen gas. Indium is added to some dental amalgam alloys to decrease the surface tension of the mercury and allow for less mercury and easier amalgamation. Indium's high neutron-capture cross-section for thermal neutrons makes it suitable for use in control rods for nuclear reactors , typically in an alloy of 80% silver , 15% indium, and 5% cadmium . In nuclear engineering,
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#17328489475844680-466: The (n,n') reactions of In and In are used to determine magnitudes of neutron fluxes. In 2009, Professor Mas Subramanian and former graduate student Andrew Smith at Oregon State University discovered that indium can be combined with yttrium and manganese to form an intensely blue , non-toxic, inert, fade-resistant pigment , YInMn blue , the first new inorganic blue pigment discovered in 200 years. Radioactive indium-111 (in very small amounts)
4770-418: The 1950s, tiny beads of indium were used for the emitters and collectors of PNP alloy-junction transistors . In the middle and late 1980s, the development of indium phosphide semiconductors and indium tin oxide thin films for liquid-crystal displays (LCD) aroused much interest. By 1992, the thin-film application had become the largest end use. Indium(III) oxide and indium tin oxide (ITO) are used as
4860-492: The Fe cations are big enough to cause some variations. The Fe radii vary from 0.49 Å to 0.92 Å, depending on the charge (2+ or 3+) and the coordination number (4 or 8). Nevertheless, the O spacings are similar for the two minerals hence hematite can readily grow on the (111) faces of magnetite, with hematite (001) parallel to magnetite (111) . Epitaxy is used in nanotechnology and in semiconductor fabrication . Indeed, epitaxy
4950-591: The InGaN/GaN alloys, theoretical approaches for AlGaN/GaN systems also apply to InGaN nanostructures. GaN is a defect-rich material with typical dislocation densities exceeding 10 cm. Light emission from InGaN layers grown on such GaN buffers used in blue and green LEDs is expected to be attenuated because of non-radiative recombination at such defects. Nevertheless, InGaN quantum wells , are efficient light emitters in green, blue, white and ultraviolet light-emitting diodes and diode lasers . The indium-rich regions have
5040-543: The atmosphere. Indium nitride is readily attacked by acids and alkalis. Indium(I) compounds are not common. The chloride, bromide , and iodide are deeply colored, unlike the parent trihalides from which they are prepared. The fluoride is known only as an unstable gas. Indium(I) oxide black powder is produced when indium(III) oxide decomposes upon heating to 700 °C. Less frequently, indium forms compounds in oxidation state +2 and even fractional oxidation states. Usually such materials feature In–In bonding, most notably in
5130-464: The availability of indium is fundamentally determined by the rate at which these ores are extracted, and not their absolute amount. This is an aspect that is often forgotten in the current debate, e.g. by the Graedel group at Yale in their criticality assessments, explaining the paradoxically low depletion times some studies cite. Indium is produced exclusively as a by-product during the processing of
5220-404: The c axis of hematite, and the c axis of rutile being parallel to one of the axes of hematite. Another example is hematite Fe 2 O 3 on magnetite Fe Fe 2 O 4 . The magnetite structure is based on close-packed oxygen anions stacked in an ABC-ABC sequence. In this packing the close-packed layers are parallel to (111) (a plane that symmetrically "cuts off"
5310-516: The capability to create dopant concentration gradients while the solution is held at constant temperature. Solid-phase epitaxy (SPE) is a transition between the amorphous and crystalline phases of a material. It is usually produced by depositing a film of amorphous material on a crystalline substrate, then heating it to crystallize the film. The single-crystal substrate serves as a template for crystal growth. The annealing step used to recrystallize or heal silicon layers amorphized during ion implantation
5400-440: The chamber. A common technique used in compound semiconductor growth is molecular beam epitaxy (MBE). In this method, a source material is heated to produce an evaporated beam of particles, which travel through a very high vacuum (10 Pa ; practically free space) to the substrate and start epitaxial growth. Chemical beam epitaxy , on the other hand, is an ultra-high vacuum process that uses gas phase precursors to generate
5490-608: The crystalline quality and optical properties began at x ~ 0.6. Films were grown at ~400 °C to facilitate indium incorporation and with precursor modulation to enhance surface morphology and metal adlayer diffusion. These findings should contribute to the development of growth techniques for nitride semiconductors under high lattice misfit conditions. Quantum heterostructures are often built from GaN with InGaN active layers. InGaN can be combined with other materials, e.g. GaN , AlGaN , on SiC , sapphire and even silicon . InGaN nanorod LEDs are three-dimensional structures with
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#17328489475845580-403: The crystals of both minerals are well formed so that the directions of the crystallographic axes are clear then the epitaxic relationship can be deduced just by a visual inspection. Sometimes many separate crystals form the overgrowth on a single substrate, and then if there is epitaxy all the overgrowth crystals will have a similar orientation. The reverse, however, is not necessarily true. If
5670-476: The energy needed to involve the 5s-electrons. Indium(I) oxide and hydroxide are more basic and indium(III) oxide and hydroxide are more acidic. A number of standard electrode potentials, depending on the reaction under study, are reported for indium, reflecting the decreased stability of the +3 oxidation state: Indium metal does not react with water, but it is oxidized by stronger oxidizing agents such as halogens to give indium(III) compounds. It does not form
5760-518: The epitaxial layer is formed when the islands join. In the FM growth mode, adsorbate-surface and adsorbate-adsorbate interactions are balanced, which promotes 2D layer-by-layer or step-flow epitaxial growth. The SK mode is a combination of VW and FM modes. In this mechanism, the growth initiates in the FM mode, forming 2D layers, but after reaching a critical thickness, enters a VW-like 3D island growth regime. Practical epitaxial growth, however, takes place in
5850-498: The epitaxial layer to the seed layer is defined in terms of the orientation of the crystal lattice of each material. For most epitaxial growths, the new layer is usually crystalline and each crystallographic domain of the overlayer must have a well-defined orientation relative to the substrate crystal structure. Epitaxy can involve single-crystal structures, although grain-to-grain epitaxy has been observed in granular films. For most technological applications, single-domain epitaxy, which
5940-528: The expected trihalides . Chlorination, bromination, and iodination of In produce colorless InCl 3 , InBr 3 , and yellow InI 3 . The compounds are Lewis acids , somewhat akin to the better known aluminium trihalides. Again like the related aluminium compound, InF 3 is polymeric. Direct reaction of indium with the pnictogens produces the gray or semimetallic III–V semiconductors . Many of them slowly decompose in moist air, necessitating careful storage of semiconductor compounds to prevent contact with
6030-533: The grown layer the thermal expansion coefficient of substrate and grown layer should be similar. Centrifugal liquid-phase epitaxy is used commercially to make thin layers of silicon , germanium , and gallium arsenide . Centrifugally formed film growth is a process used to form thin layers of materials by using a centrifuge . The process has been used to create silicon for thin-film solar cells and far-infrared photodetectors. Temperature and centrifuge spin rate are used to control layer growth. Centrifugal LPE has
6120-443: The high temperatures at which epitaxy is performed may allow dopants to diffuse into the growing layer from other layers in the wafer ( out-diffusion ). In mineralogy, epitaxy is the overgrowth of one mineral on another in an orderly way, such that certain crystal directions of the two minerals are aligned. This occurs when some planes in the lattices of the overgrowth and the substrate have similar spacings between atoms . If
6210-410: The long-lasting (up to thousands of years) s-process (slow neutron capture) in low-to-medium-mass stars (range in mass between 0.6 and 10 solar masses ). When a silver-109 atom captures a neutron, it transmutes into silver-110, which then undergoes beta decay to become cadmium-110. Capturing further neutrons, it becomes cadmium-115, which decays to indium-115 by another beta decay . This explains why
6300-422: The main-products. Recent estimates put the supply potential of indium at a minimum of 1,300 t/yr from sulfidic zinc ores and 20 t/yr from sulfidic copper ores. These figures are significantly greater than current production (655 t in 2016). Thus, major future increases in the by-product production of indium will be possible without significant increases in production costs or price. The average indium price in 2016
6390-455: The material is relatively insensitive to defects introduced by a lattice mismatch between the layers. A two-layer multijunction cell with bandgaps of 1.1 eV and 1.7 eV can attain a theoretical 50% maximum efficiency, and by depositing multiple layers tuned to a wide range of bandgaps an efficiency up to 70% is theoretically expected. Significant photoresponse was obtained from experimental InGaN single-junction devices. In addition to controlling
6480-512: The material's band gap, can be controlled by the GaN/InN ratio, from near ultraviolet for 0.02In/0.98Ga through 390 nm for 0.1In/0.9Ga, violet-blue 420 nm for 0.2In/0.8Ga, to blue 440 nm for 0.3In/0.7Ga, to red for higher ratios and also by the thickness of the InGaN layers which are typically in the range of 2–3 nm . However, atomistic simulations results have shown that emission energies have
6570-471: The melting point of the deposited semiconductor. The semiconductor is dissolved in the melt of another material. At conditions that are close to the equilibrium between dissolution and deposition, the deposition of the semiconductor crystal on the substrate is relatively fast and uniform. The most used substrate is indium phosphide (InP). Other substrates like glass or ceramic can be applied for special applications. To facilitate nucleation, and to avoid tension in
6660-468: The minerals pyrite , arsenopyrite , galena and sphalerite in hydrochloric acid and distilled raw zinc chloride . Reich, who was color-blind , employed Richter as an assistant for detecting the colored spectral lines. Knowing that ores from that region sometimes contain thallium , they searched for the green thallium emission spectrum lines. Instead, they found a bright blue line. Because that blue line did not match any known element, they hypothesized
6750-415: The molecular beam. Another widely used technique in microelectronics and nanotechnology is atomic layer epitaxy , in which precursor gases are alternatively pulsed into a chamber, leading to atomic monolayer growth by surface saturation and chemisorption . Liquid-phase epitaxy (LPE) is a method to grow semiconductor crystal layers from the melt on solid substrates. This happens at temperatures well below
6840-491: The only stable isotope , and indium-115, which has a half-life of 4.41 × 10 years, four orders of magnitude greater than the age of the Universe and nearly 30,000 times greater than half life of thorium-232 . The half-life of In is very long because the beta decay to Sn is spin-forbidden . Indium-115 makes up 95.7% of all indium. Indium is one of three known elements (the others being tellurium and rhenium ) of which
6930-464: The optical properties, which results in band gap engineering, photovoltaic device performance can be improved by engineering the microstructure of the material to increase the optical path length and provide light trapping. Growing nanocolumns on the device can further result in resonant interaction with light, and InGaN nanocolumns have been successfully deposited on SiO 2 using plasma enhanced evaporation. Nanorod growth may also be advantageous in
7020-422: The ores of other metals. Its main source material are sulfidic zinc ores, where it is mostly hosted by sphalerite. Minor amounts are also extracted from sulfidic copper ores. During the roast-leach-electrowinning process of zinc smelting , indium accumulates in the iron-rich residues. From these, it can be extracted in different ways. It may also be recovered directly from the process solutions. Further purification
7110-432: The other post-transition metal groups because of the weakness of the metallic bonding with few electrons delocalized . The density of indium, 7.31 g/cm , is also greater than gallium, but lower than thallium. Below the critical temperature , 3.41 K , indium becomes a superconductor . Indium crystallizes in the body-centered tetragonal crystal system in the space group I 4/ mmm ( lattice parameters :
7200-412: The overgrowth crystals have a similar orientation there is probably an epitaxic relationship, but it is not certain. Some authors consider that overgrowths of a second generation of the same mineral species should also be considered as epitaxy, and this is common terminology for semiconductor scientists who induce epitaxic growth of a film with a different doping level on a semiconductor substrate of
7290-409: The primordial. All decay by isomeric transition . The indium isotopes lighter than In predominantly decay through electron capture or positron emission to form cadmium isotopes, while the indium isotopes heavier than In predominantly decay through beta-minus decay to form tin isotopes. Indium(III) oxide , In 2 O 3 , forms when indium metal is burned in air or when the hydroxide or nitrate
7380-440: The radioactive isotope is more abundant than the stable one. The stable indium isotope, indium-113, is one of the p-nuclei , the origin of which is not fully understood; although indium-113 is known to be made directly in the s- and r-processes (rapid neutron capture), and also as the daughter of very long-lived cadmium-113, which has a half-life of about eight quadrillion years, this cannot account for all indium-113. Indium
7470-471: The reduction of treading dislocations which may act as charge traps reducing solar cell efficiency Metal-modulated epitaxy allows controlled atomic layer-by-layer growth of thin films with almost ideal characteristics enabled by strain relaxation at the first atomic layer. The crystal's lattice structures match up, resembling a perfect crystal, with corresponding luminosity. The crystal had indium content ranging from x ~ 0.22 to 0.67. Significant improvement in
7560-554: The same material. For naturally produced minerals, however, the International Mineralogical Association (IMA) definition requires that the two minerals be of different species. Another man-made application of epitaxy is the making of artificial snow using silver iodide , which is possible because hexagonal silver iodide and ice have similar cell dimensions. Minerals that have the same structure ( isomorphic minerals ) may have epitaxic relations. An example
7650-430: The simplest case, the epitaxial layer can be a continuation of the same semiconductor compound as the substrate; this is referred to as homoepitaxy. Otherwise, the epitaxial layer will be composed of a different compound; this is referred to as heteroepitaxy. Homoepitaxy is a kind of epitaxy performed with only one material, in which a crystalline film is grown on a substrate or film of the same material. This technology
7740-429: The stable isotope is less abundant in nature than the long-lived primordial radioisotopes. The stablest artificial isotope is indium-111 , with a half-life of approximately 2.8 days. All other isotopes have half-lives shorter than 5 hours. Indium also has 47 meta states, among which indium-114m1 (half-life about 49.51 days) is the most stable, more stable than the ground state of any indium isotope other than
7830-411: The surface, may also diffuse into the epitaxial layer and cause autodoping . The concentration of impurity in the gas phase determines its concentration in the deposited film. Doping can also be achieved by a site-competition technique, where the growth precursor ratios are tuned to enhance the incorporation of vacancies, specific dopant species or vacant-dopant clusters into the lattice. Additionally,
7920-493: The surfaces during manufacture and handling. Heteroepitaxial growth is classified into three primary growth modes-- Volmer–Weber (VW), Frank–van der Merwe (FM) and Stranski–Krastanov (SK). In the VW growth regime, the epitaxial film grows out of 3D nuclei on the growth surface. In this mode, the adsorbate-adsorbate interactions are stronger than adsorbate-surface interactions, leading to island formation by local nucleation and
8010-470: Was US$ 240/kg, down from US$ 705/kg in 2014. China is a leading producer of indium (290 tonnes in 2016), followed by South Korea (195 t), Japan (70 t) and Canada (65 t). The Teck Resources refinery in Trail, British Columbia , is a large single-source indium producer, with an output of 32.5 tonnes in 2005, 41.8 tonnes in 2004 and 36.1 tonnes in 2003. The primary consumption of indium worldwide
8100-445: Was the first known organoindium(I) compound, and is polymeric, consisting of zigzag chains of alternating indium atoms and cyclopentadienyl complexes . Perhaps the best-known organoindium compound is trimethylindium , In(CH 3 ) 3 , used to prepare certain semiconducting materials. In 1863, German chemists Ferdinand Reich and Hieronymus Theodor Richter were testing ores from the mines around Freiberg, Saxony . They dissolved
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