Spin-Polarized Electron Injection through an Fe/InAs Junction

We report on the spin-polarized electron injection through an Fe(100)/InAs(100) junction. The circularly polarized electroluminescence of injected electrons from epitaxially grown Fe thin film into InAs(100) in an external magnetic field is measured to investigate the spin injection efficiency. The obtained polarization of the electroluminescence is seen to increase up to about -12 % at the temperature of 6.5 K and the external magnetic field of 10 T. This result suggests that the efficient spin injection is possible through the ferromagnetic metal/semiconductor (FM/SC) interface without a tunneling barrier despite the contradictory arguments based on conductivity mismatch at the FM/SC interface.