Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 34: Poster I: III-V Semiconductors
HL 34.14: Poster
Tuesday, March 23, 2010, 18:30–20:30, Poster D2
Spin Injection in GaAs by Cleaved Edge Overgrowth — •Arne Ludwig1, Hasmik Harutyunyan2, Sani Noor2, Mingyuan Li3, Henning Soldat3, Dirk Reuter1, Andreas Wieck1, Ulrich Köhler2, and Martin Hofmann3 — 1Lehrstuhl für Angewandte Festkörperphysik — 2Oberflächenphysik — 3Lehrstuhl für Photonik und Terahertztechnologie, all Ruhr-Universität 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 conventional 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 to the p-doped region are evaporated before transferring the sample to a metal-MBE, where it is cleaved under ultra high vacuum conditions. Then, the FM-contacts with MgO- tunnel-barriers are evaporated in situ on the cleavage plane. The spins in this device are thus injected from the side. We will discuss the advantages of this spin injection method as well as the electroluminescence and polarization results from these diodes.