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Molecular beam epitaxy of high mobility In0.75Ga0.25As for electron spin transport applications

Simmonds, PJ; Holmes, SN; Beere, HE; Farrer, I; Sfigakis, F; Ritchie, DA; Pepper, M; (2009) Molecular beam epitaxy of high mobility In0.75Ga0.25As for electron spin transport applications. In: JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B. (pp. 2066 - 2070). A V S AMER INST PHYSICS

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Abstract

The authors describe the molecular beam epitaxy of relaxed, nominally undoped In0.75Ga0.25As-In0.75Al0.25As quantum well structures grown on InP substrates. The maximum two-dimensional electron density is 2x10(11) cm(-2), with a peak mobility of 2.2x10(5) cm(2) V-1 s(-1) at 1.5 K. In high magnetic field, the electron g-factor was shown to have a magnitude of 9.1 +/- 0.1 at Landau-level filling factor of 4. The Rashba coefficient, determined from the analysis of the magnetoresistance at high Landau-level filling factor (>12), is 1x10(-11) eV m. The mobility is sufficiently high in these two-dimensional electron gases that spin-orbit effects are observed up to 4.2 K. The interface asymmetry, defined as the difference between the wavefunction penetration into the upper and lower In0.75Al0.25As quantum barriers, makes no contribution to the Rashba spin-orbit coupling parameter in this system. Quantum wires defined in these two-dimensional electron gases using insulated, split surface gates show clear quarter-integer quantized conductance plateaux at exactly 0.25(2e(2)/h) and 0.75(2e(2)/h) in nonequilibrium transport. In0.75Ga0.25As may have important application as an alternative field effect transistor channel to silicon, and the large electronic g-factor and Rashba spin-orbit coupling parameter make this material combination suitable for exploring spin related phenomena in one-dimensional systems.

Type:Proceedings paper
Title:Molecular beam epitaxy of high mobility In0.75Ga0.25As for electron spin transport applications
Event:36th Conference of Physics and Chemistry of Surfaces and Interfaces
Location:Santa Barbara, CA
Dates:2009-01-11 - 2009-01-15
DOI:10.1116/1.3156736
Keywords:aluminium compounds, electron density, gallium arsenide, g-factor, III-V semiconductors, indium compounds, Landau levels, magnetoresistance, molecular beam epitaxial growth, semiconductor growth, semiconductor quantum wells, spin-orbit interactions, two-dimensional electron gas, QUANTUM POINT CONTACTS, MAGNETIC-FIELDS, GAS, CONDUCTANCE, SUBSTRATE, WELLS, GAAS
UCL classification:UCL > School of BEAMS > Faculty of Engineering Science > Electronic and Electrical Engineering

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