Electron scattering by ionized impurities in semiconductors

Chattopadhyay, Dipankar; Queisser, H. J.

doi:10.1103/revmodphys.53.745

Cited by 559 publications

(324 citation statements)

References 134 publications

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“…We concentrate on n-type doping regimes at which ionized impurity scattering is negligible, viz., n < 10 16 cm −3 . We corroborate this assumption by including ionized impurity scattering as in the Brooks-Herring approach [22][23][24] in the calculation of the mobility. The effective masses for electrons are taken from the calculated energy distribution of the conduction band valleys.…”

Section: Calculation and Resultssupporting

confidence: 59%

Giant piezoresistance in silicon-germanium alloys

Murphy-Armando

Fahy

2012

Phys. Rev. B

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Type of publicationArticle (peer-reviewed) We use first-principles electronic structure methods to show that the piezoresistive strain gauge factor of single-crystalline bulk n-type silicon-germanium alloys at carefully controlled composition can reach values of G = 500, three times larger than that of silicon, the most sensitive such material used in industry today. At cryogenic temperatures of 4 K we find gauge factors of G = 135 000, 13 times larger than that observed in Si whiskers. The improved piezoresistance is achieved by tuning the scattering of carriers between different ( and L) conduction band valleys by controlling the alloy composition and strain configuration.

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Section: Calculation and Resultssupporting

confidence: 59%

Giant piezoresistance in silicon-germanium alloys

Murphy-Armando

Fahy

2012

Phys. Rev. B

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“…(16) was estimated using a combined measurement of Hall and drift photoelectron mobility [40]. One finds p = 0 ± 0.5, which is close to the expected value p = 1/2 in the case where the mobility is determined by screened collisions with charged impurities or with majority holes [28,43]. This result implies that, for the present sample, the spin dependence of the mobility is weak.…”

Section: Interpretation a Calculation Of The Polarization Profilesmentioning

confidence: 64%

Effect of the Pauli principle on photoelectron spin transport inp+GaAs

et al. 2015

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In p + GaAs thin films, the effect of photoelectron degeneracy on spin transport is investigated theoretically and experimentally by imaging the spin polarization profile as a function of distance from a tightly-focussed light excitation spot. Under degeneracy of the electron gas (high concentration, low temperature), a dip at the center of the polarization profile appears with a polarization maximum at a distance of about 2 µm from the center. This counterintuitive result reveals that photoelectron diffusion depends on spin, as a direct consequence of the Pauli principle. This causes a concentration dependence of the spin stiffness while the spin dependence of the mobility is found to be weak in doped material. The various effects which can modify spin transport in a degenerate electron gas under local laser excitation are considered. A comparison of the data with a numerical solution of the coupled diffusion equations reveals that ambipolar coupling with holes increases the steady-state photo-electron density at the excitation spot and therefore the amplitude of the degeneracy-induced polarization dip. Thermoelectric currrents are predicted to depend on spin under degeneracy (spin Soret currents), but these currents are negligible except at very high excitation power where they play a relatively small role. Coulomb spin drag and bandgap renormalization are negligible due to electrostatic screening by the hole gas.

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“…Both models are based on the Born and two-body Coulomb interaction approximations, having therefore severe drawbacks to correctly describe electron-ionized impurity scattering over a wide range of impurity concentrations. There is a vast number of attempts to more rigorously investigate electron-impurity interactions (see, e.g., the review by Chattopadhyay and Queisser 18 ), but this issue is beyond the scope of the present study. We also consider InN to be uncompensated and all donors to be ionized at room temperature, thus providing that the ionized impurity concentration is equal to the doping level.…”

Section: Functional Electrical and Electronic Materials And Devicesmentioning

confidence: 72%