page_title: MOSFET applications
section_title: 2D electron gas and quantum Hall effect
hierarchical_section_title: MOSFET applications / Quantum physics / 2D electron gas and quantum Hall effect
context_page_description: The metal–oxide–semiconductor field-effect transistor, also known as the metal–oxide–silicon transistor, is a type of insulated-gate field-effect transistor that is fabricated by the controlled oxidation of a semiconductor, typically silicon. The voltage of the covered gate determines the electrical conductivity of the device; this ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. The MOSFET was invented by Egyptian engineer Mohamed M. Atalla and Korean engineer Dawon Kahng at Bell Labs in 1959. It is the basic building block of modern electronics, and the most frequently manufactured device in history, with an estimated total of 13 sextillion MOSFETs manufactured between 1960 and 2018.
  The MOSFET is the most common semiconductor device in digital and analog circuits, and the most common power device. It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses, revolutionizing the electronics industry and the world economy, having been central to the computer revolution, digital revolution, information revolution, silicon age and information age.
context_section_description: In quantum physics and quantum mechanics, the MOSFET is the basis for two-dimensional electron gas (2DEG) and the quantum Hall effect. The MOSFET enables physicists to study electron behavior in a two-dimensional gas, called a two-dimensional electron gas. In a MOSFET, conduction electrons travel in a thin surface layer, and a "gate" voltage controls the number of charge carriers in this layer. This allows researchers to explore quantum effects by operating high-purity MOSFETs at liquid helium temperatures.
  In 1978, the Gakushuin University researchers Jun-ichi Wakabayashi and Shinji Kawaji observed the Hall effect in experiments carried out on the inversion layer of MOSFETs. In 1980, Klaus von Klitzing, working at the high magnetic field laboratory in Grenoble with silicon-based MOSFET samples developed by Michael Pepper and Gerhard Dorda, made the unexpected discovery of the quantum Hall effect.
caption: A two-dimensional electron gas (2DEG) is present when a MOSFET is in inversion mode, and is found directly beneath the gate oxide.
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