![]() ![]() Hot electron effect models illustrate a correlation between power dissipated, the electron gas temperature and overheating. The simplest predicts an electron-phonon (e-p) interaction based on a clean three-dimensional free-electron model. There are a number of models to describe the hot-electron effect. Hot electrons arise generically at low temperatures even in degenerate semiconductors or metals. ![]() In such cells, the hot electron effect is the reason that a portion of the light energy is lost to heat rather than converted to electricity. ![]() For instance, some solar cells rely on the photovoltaic properties of semiconductors to convert light to electricity. In some semiconductor devices, the energy dissipated by hot electron phonons represents an inefficiency as energy is lost as heat. Because of the high effective temperatures, hot electrons are very mobile, and likely to leave the semiconductor and travel into other surrounding materials. Such electrons are characterized by high effective temperatures. If the electron receives enough energy to leave the valence band, and to surpass the conduction band, it becomes a hot electron. The energy from the photon can be transferred to an electron, exciting the electron out of the valence band, and forming an electron-hole pair. Hot electrons can be created when a high-energy photon of electromagnetic radiation (such as light) strikes a semiconductor. Consequent effects include increased leakage current and possible damage to the encasing dielectric material if the hot carrier disrupts the atomic structure of the dielectric. Hot electrons can tunnel out of the semiconductor material, instead of recombining with a hole or being conducted through the material to a collector. This greater energy affects the mobility of charge carriers and as a consequence affects how they travel through a semiconductor device. More broadly, the term describes electron distributions describable by the Fermi function, but with an elevated effective temperature. The term “hot electron” was originally introduced to describe non-equilibrium electrons (or holes) in semiconductors. The term "hot electron" comes from the effective temperature term used when modelling carrier density (i.e., with a Fermi-Dirac function) and does not refer to the bulk temperature of the semiconductor (which can be physically cold, although the warmer it is, the higher the population of hot electrons it will contain all else being equal). For holes, the valence band offset in this case dictates they must have a kinetic energy of 4.6 eV. To become “hot” and enter the conduction band of SiO 2, an electron must gain a kinetic energy of ~3.2 eV. The term “hot carrier injection” usually refers to the effect in MOSFETs, where a carrier is injected from the conducting channel in the silicon substrate to the gate dielectric, which usually is made of silicon dioxide (SiO 2). Hot-carrier injection is one of the mechanisms that adversely affects the reliability of semiconductors of solid-state devices. Since the charge carriers can become trapped in the gate dielectric of a MOS transistor, the switching characteristics of the transistor can be permanently changed. The term "hot" refers to the effective temperature used to model carrier density, not to the overall temperature of the device. Hot carrier injection ( HCI) is a phenomenon in solid-state electronic devices where an electron or a “ hole” gains sufficient kinetic energy to overcome a potential barrier necessary to break an interface state. JSTOR ( May 2011) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed.įind sources: "Hot-carrier injection" – news Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification. ![]()
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