Electron mobility
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In physics, electron mobility (or simply, mobility), is used to describe the relation between drift velocity of electrons or holes in a solid material or electrons/ions in a gas, and an applied electric field. The drift mobility is directly related to the electric field as follows,
- <math>v_d = \mu E<math>,
where μ is the mobility.
In metric units, mobility is normally measured in cm2/Vs. Since mobility is a strong function of impurities in a materials as well as temperature, it is difficult to provide any values of mobility here for common materials. Mobility is also different for electrons and holes in a semiconductor. When one charge carrier is dominant the conductivity of a semiconductor is directly proportional to the mobility of the dominant carrier.
Typical electron mobility for GaAs at room temperature is 2000 cm2/Vs.
In approximation the mobility can be written as a combination of influences from lattice vibrations (phonons) and from impurities by following equation:
- <math>\mu = \frac{1}{\frac{1}{\mu_{\rm lattice}}+\frac{1}{\mu_{\rm impurities}}}<math>.
External links
semiconductor glossary (http://semiconductorglossary.com/default.asp?searchterm=electron+mobility)