An intrinsic semiconductor, also called an undoped semiconductor or i-type semiconductor, is a pure semiconductor without any significant dopant species present. The number of charge carriers is therefore determined by the properties of the material itself instead of the amount of impurities. In intrinsic semiconductors the number of electrons and the number of holes are equal. n = p. A semiconductor is a solid whose electrical conductivity is in between that of a conductor and that of an insulator, and can be controlled over a wide range, either permanently or dynamically. ... A dopant, also called doping agent and dope, is an impurity element added to a semiconductor lattice in low concentrations in order to alter the optical/electrical properties of the semiconductor. ... Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. ... For other uses, see Electron (disambiguation). ... For the following two reasons the electron hole was introduced into calculations: If an electron is excited into higher state it leaves a hole in its old state. ...
The conductivity of intrinsic semiconductors can be due to crystal defects or to thermal excitation. In an intrinsic semiconductor the number of electrons in the conduction band is equal to the number of holes in the valence band. An example is Hg0.8Cd0.2>Te at room temperature. For other uses, see Electron (disambiguation). ... In semiconductors and insulators, the conduction band is the range of electron energy, higher than that of the valence band, sufficient to make the electrons free to accelerate under the influence of an applied electric field and thus constitute an electric current. ... In solids, the valence band is the highest range of electron energies where electrons are normally present at zero temperature. ... HgCdTe or Mercury cadmium telluride (also Cadmium Mercury Telluride or CMT) is an alloy of CdTe and HgTe and is sometimes claimed to be the third semiconductor of technological importance after Si and GaAs. ...
An indirect gap intrinsic semiconductor is one where the maximum energy of the valence band occurs at a different k (k-space wave vector) than the minimum energy of the conduction band. Examples include Silicon and Germanium. A direct gap intrinsic semiconductor is one where the maximum energy of the valence band occurs at the same k as the minimum energy of the conduction band. Examples include Gallium arsenide.
A layer of i-type semiconductor is used in PIN diodes. Layers of a PIN diode PIN diode is a diode with a wide, undoped intrinsic semiconductor region between p-type semiconductor and n-type semiconductor regions. ...
References
Sze, Simon M. (1981). Physics of Semiconductor Devices (2nd ed.). John Wiley and Sons (WIE). ISBN 0-471-05661-8.
Kittel, Ch. (2004). Introduction to Solid State Physics. John Wiley and Sons. ISBN 0-471-41526-X.
A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor.
A semiconductor has a band gap which is small enough such that its conduction band is appreciably thermally populated with electrons at room temperature, whilst an insulator has a band gap which is too wide for there to be appreciable thermal electrons in its conduction band at room temperature.
The ease with which electrons in a semiconductor can be excited from the valence band to the conduction band depends on the band gap between the bands, and it is the size of this energy bandgap that serves as an arbitrary dividing line between semiconductors and insulators.
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