  We report electrical spin injection and detection in degenerately doped
n-type Ge channels using Mn5Ge3C0.8/Al2O3/n^{+}-Ge tunneling contacts for spin
injection and detection. The whole structure is integrated on a Si wafer for
complementary metal-oxide-semiconductor compatibility. From three-terminal
Hanle-effect measurements, we observe a spin accumulation up to 10 K. The spin
lifetime is extracted to be 38 ps at T = 4K using Lorentzian fitting, and the
spin diffusion length is estimated to be 367 nm due to the high diffusion
coefficient of the highly doped Ge channel.
