Spin Transport Properties in Nondegenerate Si at Room Temperature

So-called beyond-CMOS technologies have been intensively investigated. Among them, Si spintronics is now a promising candidate, since Si has good spin coherence, enabling novel spin-based logic systems. We have been investigating spin transport properties in degenerate Si up to room temperature (RT)),\footnote{T. Suzuki, T. Sasaki, M. Shiraishi et al., Appl. Phys. Exp. 4, 023003 (2011)} and recently, spin transport in a non-degenerate n-Si at RT was successfully achieved,\footnote{T. Sasaki, T. Tahara, M. Shiraishi et al., Phys. Rev. Applied, 2, 034005 (2014).} where the doping concentration of Si was $2\times10^{18}$ cm$^{-3}$. Spin drift in non-degenerate Si allows apparent modulation of Hanle spin signals under applications of bias- and gate-electric fields.\footnote{Sasaki, Phys. Rev. Applied, 2, 034005 (2014).} The magnitude of the spin signals exceeds 1 mV under an bias electric current of 1 mA, which is ten times greater than previously reported values\footnote{T. Sasaki, M. Shiraishi et al., Appl. Phys. Lett. 104, 052404 (2014).} in degenerate-Si-based spin transport devices. The detail of the observation of large spin signals and other spin transport properties will be discussed in the presentation.