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HL: Fachverband Halbleiterphysik
HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties
HL 91.30: Poster
Donnerstag, 14. März 2013, 16:00–20:00, Poster A
Study of Phase-Coherent Transport in Differently Doped InAs Nanowires — •Thomas Gerster1, Sebastian Heedt1, Isabel Wehrmann1,2, Kamil Sladek1, Hilde Hardtdegen1, Detlev Grützmacher1, and Thomas Schäpers1,3 — 1Peter Grünberg Institut (PGI-9) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany — 2OSRAM Opto Semiconductors GmbH, 93055 Regensburg, Germany — 3II. Physikalisches Institut, RWTH Aachen University, 52056 Aachen, Germany
We report on differently doped InAs nanowires grown epitaxially by selective area metalorganic vapor phase epitaxy. The nanowires are individually contacted with Ω-shaped top-gates using high-k dielectrics to investigate the low-temperature electronic transport properties. The band profile and the carrier concentration of the nanowires can be manipulated by the application of a gate voltage. At small current-bias, phase-coherent transport occurs and gives us the ability to determine the phase-coherence length lφ and the spin relaxation length lso. In our measurement setup, phase-coherent transport is investigated for temperatures down to 30 mK and magnetic fields up to 10 T. To extract lφ and lso, we make use of an analytical model for the low-field quantum conductivity correction. This model considers spin relaxation under linear Rashba and linear and cubic Dresselhaus spin-orbit coupling for diffusive wires with diameters smaller than lφ. The impact of doping on the electron spin lifetime is studied for InAs nanowires fabricated under various doping conditions.