Modeling of magnetically controlled Si-based optoelectronic devices

We present a theoretical analysis and results of modeling of a new integrated device for spintronics application, which is based on a hybrid metal–semiconductor structure. The proposed device consists of a Si-based p–i–n photodetector sandwiched between two layers of a ferromagnetic metal (3d ferromagnet or half-metallic compound). Electron–hole pairs are created in the semiconductor part of the structure by light illumination. The photocurrent flowing in such a system is shown to depend on its magnetic configuration. This is due to a difference in the specular reflection (as well as in the diffuse scattering) of spin-up and spin-down electrons and holes from magnetically polarized layers—similar to giant magnetoresistance effect in magnetic multilayers. This, in turn, allows controlling the device performance by an externally applied magnetic field. We have estimated magnitude of the effect and also determined the role of relevant material parameters.