IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI+EL-TuA

Paper MI+EL-TuA6
Effects of Interface Structure and Chemistry on Spin Injection Efficiency in Spin-LEDs

Tuesday, October 30, 2001, 3:40 pm, Room 110

Session: Spintronics II: Spin Injection & Transport
Presenter: R.M. Stroud, Naval Research Laboratory
Authors: R.M. Stroud, Naval Research Laboratory
Y.D. Park, Naval Research Laboratory
A.T. Hanbicki, Naval Research Laboratory
B.R. Bennet, Naval Research Laboratory
B.T. Jonker, Naval Research Laboratory
G. Itskos, SUNY Buffalo
M. Furis, SUNY Buffalo
G. Kioseoglou, SUNY Buffalo
A. Petrou, SUNY Buffalo
Correspondent: Click to Email

The efficiency of spin injection across a heterointerface can be strongly affected by the structure and chemistry of that interface. To quantify the relationship between interface quality and spin injection efficiency, spin-LEDs make an ideal test system. In a spin-LED, carriers with a net spin polarization are injected into a LED, where radiative recombination results in circularly polarized light emission. The optical circular polarization directly reflects the degree of the spin polarization of the injected current. By varying the growth conditions to vary the quality of the interface for ZnMnSe/AlGaAs/GaAs/AlGaAs spin-LEDs, injection efficiencies of 0 to 65% have been achieved. In this system, the primary structural defect, identified by cross sectional transmission electron microscopy, is a stacking fault that nucleates at the ZnMnSe/AlGaAs interface. Stacking fault densities ranged from 10@super 10@ cm@super -2@ for the lowest efficiency samples to < 10@super 8@ cm@super -2@ for the 65% efficiency sample., The optical polarization scales with the stacking fault density, which indicates that the spin injection efficiency is affected by the ZnMnSe/AlGaAs interface structure and chemistry. We compare results for growth on As- and Ga-terminated AlGaAs surfaces, and for structures grown with a Zn- and Se-initiated growth of the ZnMnSe polarized contact layer. These results demonstrate that although the spin injection efficiency is sensitive to interface quality, the spin injection effect is robust enough in all-semicondutor spin-LEDS to withstand moderately high defect densities, and can be produced using pre-grown LEDs. @FootnoteText@ @footnote 1@ This work supported by ONR and the DARPA SpinS program.