Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Poster II
HL 31.6: Poster
Dienstag, 26. Februar 2008, 16:30–19:00, Poster D
Spin Injection in GaAs by Cleaved-Edge-Overgrowth — •Arne Ludwig1, Carsten Godde2, Sani Noor2, Stephan Hövel3, Dirk Reuter1, Andreas D. Wieck1, Ulrich Köhler2, and Martin Hofmann3 — 1Lehrstuhl für Angewandte Festkörperphysik — 2Experimentalphysik IV - AG Oberflächenphysik — 3Arbeitsgruppe Optoelektronische Bauelemente und Werkstoffe, all Ruhr-Universität Bochum, D-44780 Bochum
Spin injection in semiconductors is still a challenging topic. Successful spin injection has been demonstrated by the detection of circularly polarized light, resulting from the recombination of spin polarized electrons and unpolarized holes in a n-i-p-diode. In a classic approach, the spins are injected from a ferromagnetic metal grown on top of the n-i-p diode. At the interface either a tailored Schottky barrier or an inserted MgO layer serves as tunnel-barrier into the n-doped region of the device. Some technical problems occur, e. g., protecting the semiconductor surface from impurities before depositing the metal/tunnelling barrier and the need for a magnetic material with out-of-plane anisotropy. In our approach, the sample is patterned and ohmic contacts are evaporated before transferring the sample to a metal-MBE, where it is cleaved under ultra high vacuum conditions. Then, the FM-contacts are evaporated in situ on the cleavage plane. In addition to Schottky barrier contacts, MgO tunnel-barriers have been prepared. We will discuss the properties of the different contact configurations.