Semiconductors in the context of "Field emission"

Motorola, Inc. (/ˌmoʊtəˈroʊlə/), was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been radio-related communication equipment such as two-way radios, consumer walkie-talkies, cellular infrastructure, mobile phones, satellite communicators, pagers, as well as cable modems and semiconductors. After having lost $4.3 billion from 2007 to 2009, Motorola was split into two independent public companies: Motorola Solutions (its legal successor) and Motorola Mobility (spun off), on January 4, 2011.

Motorola designed and sold wireless network equipment such as cellular transmission base stations and signal amplifiers. Its business and government customers consisted mainly of wireless voice and broadband systems (used to build private networks), and public safety communications systems like Astro and Dimetra. Motorola's home and broadcast network products included set-top boxes, digital video recorders, and network equipment used to enable video broadcasting, computer telephony, and high-definition television. These businesses, except for set-top boxes and cable modems, became part of Motorola Solutions after the split of Motorola in 2011.

In solid-state physics and solid-state chemistry, a band gap, also called a bandgap or energy gap, is an energy range in a solid where no electronic states exist. In graphs of the electronic band structure of solids, the band gap refers to the energy difference (often expressed in electronvolts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote an electron from the valence band to the conduction band. The resulting conduction-band electron (and the electron hole in the valence band) are free to move within the crystal lattice and serve as charge carriers to conduct electric current. It is closely related to the HOMO/LUMO gap in chemistry. If the valence band is completely full and the conduction band is completely empty, then electrons cannot move within the solid because there are no available states. If the electrons are not free to move within the crystal lattice, then there is no generated current due to no net charge carrier mobility. However, if some electrons transfer from the valence band (mostly full) to the conduction band (mostly empty), then current can flow (see carrier generation and recombination). Therefore, the band gap is a major factor determining the electrical conductivity of a solid. Substances having large band gaps (also called "wide" band gaps) are generally insulators, those with small band gaps (also called "narrow" band gaps) are semiconductors, and conductors either have very small band gaps or none, because the valence and conduction bands overlap to form a continuous band.

It is possible to produce laser induced insulator-metal transitions which have already been experimentally observed in some condensed matter systems, like thin films of C₆₀, doped manganites, or in vanadium sesquioxide V₂O₃. These are special cases of the more general metal-to-nonmetal transitions phenomena which were intensively studied in the last decades. A one-dimensional analytic model of laser induced distortion of band structure was presented for a spatially periodic (cosine) potential. This problem is periodic both in space and time and can be solved analytically using the Kramers-Henneberger co-moving frame. The solutions can be given with the help of the Mathieu functions.

In semiconductor production, doping is the intentional introduction of impurities into an intrinsic (undoped) semiconductor for the purpose of modulating its electrical, optical and structural properties. The doped material is referred to as an extrinsic semiconductor.

Small numbers of dopant atoms can change the ability of a semiconductor to conduct electricity. When on the order of one dopant atom is added per 100 million intrinsic atoms, the doping is said to be low or light. When many more dopant atoms are added, on the order of one per ten thousand atoms, the doping is referred to as high or heavy. This is often shown as n+ for n-type doping or p+ for p-type doping. (See the article on semiconductors for a more detailed description of the doping mechanism.) A semiconductor doped to such high levels that it acts more like a conductor than a semiconductor is referred to as a degenerate semiconductor. A semiconductor can be considered i-type semiconductor if it has been doped in equal quantities of p and n.

In semiconductors, the band gap of a semiconductor can be of two basic types, a direct band gap or an indirect band gap. The minimal-energy state in the conduction band and the maximal-energy state in the valence band are each characterized by a certain crystal momentum (k-vector) in the Brillouin zone. If the k-vectors are different, the material has an "indirect gap". The band gap is called "direct" if the crystal momentum of electrons and holes is the same in both the conduction band and the valence band; an electron can directly emit a photon. In an "indirect" gap, a photon cannot be emitted because the electron must pass through an intermediate state and transfer momentum to the crystal lattice.

Examples of direct bandgap materials include hydrogenated amorphous silicon and some III–V materials such as InAs and GaAs. Indirect bandgap materials include crystalline silicon and Ge. Some III–V materials are indirect bandgap as well, for example AlSb.

The Czochralski method, also Czochralski technique or Czochralski process, is a method of crystal growth used to obtain single crystals (monocrystals) of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold), salts and synthetic gemstones. The method is named after Polish scientist Jan Czochralski, who invented the method in 1915 while investigating the crystallization rates of metals. He made this discovery by accident: instead of dipping his pen into his inkwell, he dipped it in molten tin, and drew a tin filament, which later proved to be a single crystal. The process remains economically important, as roughly 90% of all modern-day semiconductor devices use material derived from this method.

The most important application may be the growth of large cylindrical ingots, or boules, of single crystal silicon used in the electronics industry to make semiconductor devices like integrated circuits. Other semiconductors, such as gallium arsenide, can also be grown by this method, although lower defect densities in this case can be obtained using variants of the Bridgman–Stockbarger method. Other semiconductors such as Silicon Carbide are grown using other methods such as physical vapor transport.

Fairchild Camera and Instrument Corporation was a company founded by Sherman Fairchild. It was based on the East Coast of the United States, and provided research and development for flash photography equipment. The technology was primarily used for DOD spy satellites.The firm was later known for its manufacture of semiconductors.

Mitsubishi Electric Corporation (三菱電機株式会社, Mitsubishi Denki kabushikigaisha; formerly branded as メルコ, MELCO) is a Japanese multinational electronics (appliances & consumer electronics) and electrical equipment manufacturing company headquartered in Tokyo, Japan. The company was established in 1921 as a spin-off from the electrical machinery manufacturing division of Mitsubishi Shipbuilding (Mitsubishi Heavy Industries) at the Kobe Shipyard.

A member of the Mitsubishi Group, Mitsubishi Electric produces elevators and escalators, high-end home appliances, air conditioning, factory automation systems, train systems, electric motors, pumps, semiconductors, digital signage, and satellites.