Coupling electron’s spin degree of freedom with the traditional bandgap engineering of semiconductors is envisioned to have profound impacts on the existing electronics. In our group, we focus on the development of semiconductor-based Spintronics devices for non-volatile, low-power-dissipation and beyond CMOS applications.
The critical challenge for semiconductor Spintronics is the electrical creation of spin accumulation in otherwise non-magnetic semiconductors. We utilize tunneling transport through an Fe/MgO/Ge junction to electrically create spin accumulation in Ge. The as-grown MgO on Ge is single crystalline and atomically smooth, with unique 45 degree rotation of the unit cell with respect to that of the Ge (article link). This high quality junction not only alleviates the Fermi level pinning at the Ge surface to favor electronic transport (article link), but also leads to an enhanced spin polarization of the injected electrons due to the symmetry induced spin filtering. Surface doping in Ge is utilized to facilitate tunneling transport to overcome the conductivity mismatch problem (article link). The spin injection and transport in Ge are currently under characterization.