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The hole mobility is defined by a similar equation: =. Both electron and hole mobilities are positive by definition. Usually, the electron drift velocity in a material is directly proportional to the electric field, which means that the electron mobility is a constant (independent of the electric field).
Electron and hole trapping in the Shockley-Read-Hall model. In the SRH model, four things can happen involving trap levels: [11] An electron in the conduction band can be trapped in an intragap state. An electron can be emitted into the conduction band from a trap level. A hole in the valence band can be captured by a trap.
The "holes" are, in effect, electron vacancies in the valence-band electron population of the semiconductor and are treated as charge carriers because they are mobile, moving from atom site to atom site. In n-type semiconductors, electrons in the conduction band move through the crystal, resulting in an electric current.
where g s = 2, due to spin degeneracy, e is the electron charge, h is the Planck constant, and are the Fermi levels of A and B, M(E) is the number of propagating modes in the channel, f′(E) is the deviation from the equilibrium electron distribution (perturbation), and T(E) is the transmission probability (T = 1 for ballistic).
In a semiconductor with an arbitrary density of states, i.e. a relation of the form = between the density of holes or electrons and the corresponding quasi Fermi level (or electrochemical potential) , the Einstein relation is [11] [12] =, where is the electrical mobility (see § Proof of the general case for a proof of this relation).
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 ...
Electrical mobility is the ability of charged particles (such as electrons or protons) to move through a medium in response to an electric field that is pulling them. The separation of ions according to their mobility in gas phase is called ion mobility spectrometry, in liquid phase it is called electrophoresis.
Since the electron charge e is known and also the Planck constant h, one can derive the electron density n of a sample from this plot. [3] Shubnikov–De Haas oscillations are observed in highly doped Bi 2 Se 3. [4] Fig 3 shows the reciprocal magnetic flux density 1/B i of the 10th to 14th minima of a Bi 2 Se 3 sample.