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-TuP

Paper MI-TuP2
Component-resolved Electroluminescence from Spin-LED Structures: Implications for Quantifying Electrical Spin Injection in Semiconductors

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Emerging Materials & Nanostructures Poster Session
Presenter: B.T. Jonker, Naval Research Laboratory
Authors: B.T. Jonker, Naval Research Laboratory
A.T. Hanbicki, Naval Research Laboratory
Y.D. Park, Naval Research Laboratory
B.R. Bennett, Naval Research Laboratory
M. Furis, State University of New York, Buffalo
G. Kioseoglou, State University of New York, Buffalo
D. Coffey, State University of New York, Buffalo
A. Petrou, State University of New York, Buffalo
Correspondent: Click to Email
The spin-polarized light emitting diode (spin-LED)@footnote 1@ has emerged as a very effective tool for accurately quantifying electrical spin injection in a model independent manner.@footnote 2@ The quantum selection rules which describe the radiative recombination process provide a direct and quantitative link between the circular polarization of the electroluminescence (EL) and the spin polarization of the electrically injected carriers. While these selection rules apply only to the free exciton and free carrier radiative recombination, the EL spectrum often consists of contributions from various recombination processes whose relative spectral weighting depends upon details of the LED heterostructure, such as doping, impurities and interface roughness. Common contributions include donor and acceptor-bound excitons, phonon replicas, and recombination mediated by various impurity levels or complexes. These components may completely dominate the spectrum in many instances. We resolve and identify such components in the EL spectra from several GaAs quantum well-based spin-LED structures by correlating reflectivity measurements with their dependence on doping, temperature and magnetic field, and examine the circular polarization of each. We show that these components exhibit markedly different polarizations which do not accurately reflect the electrical spin injection efficiency. Certain of these features derive from many-body effects, and may provide insight into related spin relaxation processes. We show that a reliable measure of spin injection efficiency can be obtained only if one takes care to spectroscopically resolve and accurately identify the origin of the components of the spin-LED EL spectrum. This work was supported by the DARPA SpinS program and ONR. . @FootnoteText@ @footnote 1@ B.T. Jonker, US patent # 5, 874,749 (filed 1993, issued 1999). @footnote 2@Fiederling, et al, Nature 402, 787 (1999), Jonker, et al. PRB 62, 8180 (2000), Park et al, APL 77, 3989 (2000).