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Charge carrier density, also known as carrier concentration, denotes the number of charge carriers per volume. In SI units, it is measured in m −3. As with any density, in principle it can depend on position. However, usually carrier concentration is given as a single number, and represents the average carrier density over the whole material.
Typical electron mobility at room temperature (300 K) in metals like gold, copper and silver is 30–50 cm 2 /(V⋅s). Carrier mobility in semiconductors is doping dependent. In silicon (Si) the electron mobility is of the order of 1,000, in germanium around 4,000, and in gallium arsenide up to 10,000 cm 2 /(V⋅s).
Thus, k e increases with the electrical conductivity σe and temperature T, as the Wiedemann–Franz law presents [k e /(σ e T e) = (1/3)(πk B /e c) 2 = 2.44 × 10 −8 W-Ω/K 2]. Electron transport (represented as σ e) is a function of carrier density n e,c and electron mobility μ e (σ e = e c n e,c μ e).
Generally, the carrier mobility μ depends on temperature T, on the applied electric field E, and the concentration of localized states N. Depending on the model, increased temperature may either increase or decrease carrier mobility, applied electric field can increase mobility by contributing to thermal ionization of trapped charges, and ...
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. The term "hot" refers to the effective temperature used to model carrier density, not to the overall temperature of the device.
The conventional "hole" current is in the negative direction of the electron current and the negative of the electrical charge which gives I x = ntw(−v x)(−e) where n is charge carrier density, tw is the cross-sectional area, and −e is the charge of each electron.
With some semimetals, like arsenic and antimony, there is a temperature-independent carrier density below room temperature (as in metals) while, in bismuth, this is true at very low temperatures but at higher temperatures the carrier density increases with temperature giving rise to a semimetal-semiconductor transition. A semimetal also differs ...
The dependence of carrier lifetime on the carrier density is expressed as: [9] ... T is the temperature, and is the time derivative of the open ...