Spin-dependent electrical hole extraction from low doped p-Si via the interface states in a Fe3Si/p-Si structure

Spin accumulation effect in Fe3Si/p-Si structure with low boron doped silicon substrate was found. Calculated spin lifetimes are comparable with results reported earlier but for structures with highly doped semiconductors (SC) with or without a tunnel barrier introduced between the SC and ferromagnet (FM). Electrical characterization of a prepared Fe3Si/p-Si diode allowed the determination of possible reasons for the pronounced spin signal. Analysis of the forward bias I-V curve revealed a Schottky barrier at the Fe3Si/p-Si interface with a height of phi(Bp) = 0.57 eV. Then, using impedance spectroscopy, we observed interface states localized in the band gap of silicon with energy of E-LS = 40 meV. Such states most probably cause the observed spin signal. We believe that in our experiment, spin-dependent hole extraction was performed via the interface states resulting in the minority spin accumulation in the silicon valence band. The observed effect paves the way to the development of different spintronic devices based on FM/SC structures without dielectric tunneling barriers.