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Magnetic Semiconductor
Magnetic semiconductors are semiconductor materials that exhibit both ferromagnetism (or a similar response) and useful semiconductor properties. If implemented in devices, these materials could provide a new type of control of conduction. Whereas traditional electronics are based on control of charge carriers ( n- or p-type), practical magnetic semiconductors would also allow control of quantum spin state (up or down). This would theoretically provide near-total spin polarization (as opposed to iron and other metals, which provide only ~50% polarization), which is an important property for spintronics applications, e.g. spin transistors. While many traditional magnetic materials, such as magnetite, are also semiconductors (magnetite is a semimetal semiconductor with bandgap 0.14 eV), materials scientists generally predict that magnetic semiconductors will only find widespread use if they are similar to well-developed semiconductor materials. To that end, dilute magnetic se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Material
A semiconductor is a material with electrical conductivity between that of a Electrical conductor, conductor and an Insulator (electricity), insulator. Its conductivity can be modified by adding impurities ("doping (semiconductor), doping") to its crystal structure. When two regions with different doping levels are present in the same crystal, they form a semiconductor junction. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called "metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits, and others. Silicon is a critical element for fabricating most electronic circuits. Semiconductor devices can display a range of diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Oxide
Zinc oxide is an inorganic compound with the Chemical formula, formula . It is a white powder which is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, Zinc metabolism, food supplements, rubbers, plastics, ceramics, glass, cement, lubricants, paints, sunscreens, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, semi conductors, and first-aid tapes. Although it occurs naturally as the mineral zincite, most zinc oxide is produced synthetically. History Early humans probably used zinc compounds in processed and unprocessed forms, as paint or medicinal ointment; however, their composition is uncertain. The use of ''pushpanjan'', probably zinc oxide, as a salve for eyes and open wounds is mentioned in the Indian medical text the Charaka Samhita, thought to date from 500 BC or before. Zinc oxide ointment is also mentioned by the Greek physician Dioscorides (1st century AD). Galen suggested treatin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GaMnAs
Gallium manganese arsenide, chemical formula is a magnetic semiconductor. It is based on the world's second most commonly used semiconductor, gallium arsenide, (chemical formula ), and readily compatible with existing semiconductor technologies. Differently from other dilute magnetic semiconductors, such as the majority of those based on II-VI semiconductors, it is not paramagnetic but ferromagnetic, and hence exhibits hysteretic magnetization behavior. This memory effect is of importance for the creation of persistent devices. In , the manganese atoms provide a magnetic moment, and each also acts as an acceptor, making it a ''p''-type material. The presence of carriers allows the material to be used for spin-polarized currents. In contrast, many other ferromagnetic magnetic semiconductors are strongly insulating and so do not possess free carriers. is therefore a candidate material for spintronic devices but it is likely to remain only a testbed for basic research as its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese
Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent, as a rubber additive, and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide. Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes. Manganese is commonly found in labo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium Arsenide
Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), 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. History Gallium arsenide was first synthesized and studied by Victor Goldschmidt in 1926 by passing arsenic vapors mixed with hydrogen over gallium(III) oxide at 600 °C. The semiconductor properties of GaAs and other Compound semiconductor, III-V compounds were patented by Heinrich Welker at Siemens-Schuckert in 1951 and described in a 1952 publication. Commercial production of its monocrystals commenced in 1954, and more studies followed in the 195 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indium Arsenide
Indium arsenide, InAs, or indium monoarsenide, is a narrow-bandgap semiconductor composed of indium and arsenic. It has the appearance of grey cubic crystals with a melting point of 942 °C. Indium arsenide is similar in properties to gallium arsenide and is a direct bandgap material, with a bandgap of 0.35 eV at room temperature. Indium arsenide is used for the construction of infrared detectors, for the wavelength range of 1.0–3.8 μm. The detectors are usually photovoltaic photodiodes. Cryogenically cooled detectors have lower noise, but InAs detectors can be used in higher-power applications at room temperature as well. Indium arsenide is also used for making diode lasers. InAs is well known for its high electron mobility and narrow energy bandgap. It is widely used as a terahertz radiation Terahertz radiation – also known as submillimeter radiation, terahertz waves, tremendously high frequency (THF), T-rays, T-waves, T-light, T-lux or THz – consis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Semiconductors
Semiconductor materials are nominally small band gap insulators. The defining property of a semiconductor material is that it can be compromised by doping it with impurities that alter its electronic properties in a controllable way. Because of their application in the computer and photovoltaic industry—in devices such as transistors, lasers, and solar cells—the search for new semiconductor materials and the improvement of existing materials is an important field of study in materials science. Most commonly used semiconductor materials are crystalline inorganic solids. These materials are classified according to the periodic table groups of their constituent atoms. Different semiconductor materials differ in their properties. Thus, in comparison with silicon, compound semiconductors have both advantages and disadvantages. For example, gallium arsenide (GaAs) has six times higher electron mobility than silicon, which allows faster operation; wider band gap, which allows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tohoku University
is a public research university in Sendai, Miyagi, Japan. It is colloquially referred to as or . Established in 1907 as the third of the Imperial Universities, after the University of Tokyo and Kyoto University, it initially focused on science and medicine, later expanding to include humanities studies as well. In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university's three core values are "Research First (研究第一主義)," "Open-Doors (門戸開放)," and "Practice-Oriented Research and Education (実学尊重)." History On 22 June 1907 (Mēji 40), Tohoku Imperial University (東北帝國大學, Tōhoku teikoku daigaku) was established by the Meiji government as the third Imperial University of Japan, after Tokyo Imperial University (1877) and Kyoto Imperial University (1897). From its inception, it advocated 'Open-door' policies, becoming the first university in Japan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hideo Ohno
Hideo Ohno (; Hideo Ōno; born 18 December 1954, Tokyo) is a Japanese physicist. He is the 22nd president of Tohoku University, succeeding Susumu Satomi in April 2018. Biography Ohno received B.S., M.S. and Ph.D. degrees from the University of Tokyo in 1977, 1979 and 1982. He spent one year as a visiting graduate student at Cornell University in 1979. He was a lecturer at the School of Engineering at Hokkaido University from 1982 to 1983, and an associate professor from 1983 to 1994. He was a visiting scientist at IBM T. J. Watson Research Center from 1988 to 1990. In 1994 Ohno was appointed a professor at Tohoku University and a professor at the Research Institute of Electrical Communication (RIEC) from 1995. In 2004 he became the head of the laboratory of Nanoelectronics and Spintronics at Tohoku University is a public research university in Sendai, Miyagi, Japan. It is colloquially referred to as or . Established in 1907 as the third of the Imperial Universities, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatase
Anatase is a metastable mineral form of titanium dioxide (TiO2) with a Tetragonal crystal system, tetragonal crystal structure. Although colorless or white when pure, anatase in nature is usually a black solid due to impurities. Three other Polymorphism (materials science), polymorphs (or mineral forms) of titanium dioxide are known to occur naturally: brookite, akaogiite, and rutile, with rutile being the most common and most Chemical stability, stable of the bunch. Anatase is formed at relatively low temperatures and found in minor concentrations in Igneous rock, igneous and Metamorphic rock, metamorphic rocks. Glass coated with a thin film of TiO2 shows Anti-fog, antifogging and Self-cleaning surfaces, self-cleaning properties under ultraviolet radiation. Anatase is always found as small, isolated, and sharply developed crystals, and like rutile, it crystallizes in a Tetragonal crystal system, tetragonal system. Anatase is metastable at all temperatures and pressures, with ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable, unalloyed metallic form. This means that copper is a native metal. This led to very early human use in several regions, from . Thousands of years later, it was the first metal to be smelted from sulfide ores, ; the first metal to be cast into a shape in a mold, ; and the first metal to be purposely alloyed with another metal, tin, to create bronze, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-emitting Diode
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs, and in seven-segment displays. Later developments produced LEDs available in visible, ultraviolet (U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
