  We first report the all-electrical spin injection and detection in
CoFe/MgO/moderately doped n-Ge contact at room temperature (RT), employing
threeterminal Hanle measurements. A sizable spin signal of ~170 k{\Omega}
{\mu}m^2 has been observed at RT, and the analysis using a single-step
tunneling model gives a spin lifetime of ~120 ps and a spin diffusion length of
~683 nm in Ge. The observed spin signal shows asymmetric bias and temperature
dependences which are strongly related to the asymmetry of the tunneling
process.
