Electrical spin injection from a magnetic Schottky tunnel contact into a semiconductor

Summary form only given. We describe how a ferromagnetic metal employed as a conventional Schottky barrier contact provides a practical and robust means of injecting spin-polarized carriers into a semiconductor device heterostructure, with spin injection efficiencies of 30 % extending to room temperature. The Schottky barrier formed at the Fe/AlGaAs interface provides a natural tunnel barrier for injection of spin polarized electrons under reverse bias. These carriers radiatively recombine in an AlGaAs/GaAs quantum well, emitting circularly polarized light, and the quantum selection rules which relate the optical and carrier spin polarizations provide a quantitative, model-independent measure of spin injection efficiency. Electroluminescence spectra from an Fe/AlGaAs/GaAs spin-LED exhibit significant circular polarization. The temperature dependence of the optical polarization and corresponding spin injection efficiency are determined. These results demonstrate that spin injecting contacts can be formed using a widely employed contact methodology, providing a ready pathway for the integration for spin transport into semiconductor processing technology.