AVS 50th International Symposium
    Magnetic Interfaces and Nanostructures Friday Sessions
       Session MI+SC-FrM

Paper MI+SC-FrM5
Spin Injection Across (110) Interfaces: Fe/GaAs(110) Quantum Well Spin-LEDs

Friday, November 7, 2003, 9:40 am, Room 316

Session: Semiconductor Spin Injection
Presenter: C.H. Li, Naval Research Laboratory
Authors: C.H. Li, Naval Research Laboratory
A.T. Hanbicki, Naval Research Laboratory
G. Kioseoglou, Naval Research Laboratory
O.M.J. van 't Erve, Naval Research Laboratory
B.T. Jonker, Naval Research Laboratory
G. Itskos, SUNY Buffalo
R. Mallory, SUNY Buffalo
M. Yasar, SUNY Buffalo
A. Petrou, SUNY Buffalo
Correspondent: Click to Email
Spin-LEDs can be used to reliably measure spin injection efficiency via the quantum selection rules subject to the limits imposed by the ratio of spin to radiative lifetimes. However, to date they have been implemented only in (001) oriented GaAs or InGaAs quantum wells (QWs), where the spin lifetime is shorter, resulting in an underestimate of spin injection efficiency. Recent work has shown that the spin lifetime is longer in (110) GaAs QWs, and increases with temperature.@footnote 1@ In this study we investigate spin injection in (110) oriented spin-LED QW structures to take advantage of this, and to explore the effects of band structure and the non-polar interface on spin injection. AlGaAs/GaAs LEDs have been grown on (110) substrates by molecular beam epitaxy at 450 oC and an As/Ga flux ratio of 20. Atomic force microscopy shows excellent surface morphology with a RMS roughness less than 0.5 nm. Photoluminescence is dominated by the QW excitonic emission with a linewidth of 8 meV. Initial electroluminescence results using a tailored Fe Schottky tunnel barrier injector show that a 10% spin polarization in the GaAs QW has been achieved due to injection across the Fe/AlGaAs(110) interface. The temperature dependence of the polarization, as well as comparison with (001) oriented samples and first principles theory will be presented. @FootnoteText@ Supported by DARPA, ONR, and NSF. @FootnoteText@@footnote 1@Y. Ohno et. al., PRL 83, 4196 (1999).