Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 91: Poster Session: Spintronics / Magnetic Semiconductors / Transport
HL 91.15: Poster
Donnerstag, 29. März 2012, 16:00–19:00, Poster D
Spin Injection from Ferromagnetic Contacts into InAs Nanowires — •Isabel Wehrmann1,2, Sebastian Heedt1,2, Torsten Rieger1,2, Kamil Sladek1,2, Daniel Bürgler2,3, Detlev Grützmacher1,2, and Thomas Schäpers1,2,4 — 1Peter Grünberg Institut -9, Forschungszentrum Jülich, 52425 Jülich, Germany — 2JARA-Fundamentals of Future Information Technology — 3Peter Grünberg Institut -6, Forschungszentrum Jülich, 52425 Jülich, Germany — 4II. Physikalisches Institut, RWTH Aachen, 52056 Aachen, Germany
InAs nanowires grown either by MBE (molecular beam epitaxy) or by MOVPE (metalorganic vapour phase epitaxy) are contacted by two ferromagnetic strips (Co) to inject a spin-polarized current into the semiconducting nanowire. Because of the "conductivity mismatch" (difference in carrier concentration of InAs NW and Co contacts), a tunnel barrier, e.g. a thin layer of MgO or Al2O3, is required. In order to obtain a well-defined axis of magnetization and to achieve a continuous ferromagnetic contact area, the structure has to be planarized by using HSQ (hydrogen silsesquioxane) resist before Co is deposited. To prepare a defined thickness of the tunnel barrier, the native oxide is removed by in situ sputtering before the oxide layer is deposited by MBE. The ferromagnet-insulator-semiconductor junctions are characterized electrically. To prove whether spin injection has occurred, spin-valve measurements are performed in a non-local measurement geometry as well as the measurement of the spin dephasing in a Hanle setup.