  The polarization of conduction electron spins due to an electrical current is
observed in strained nonmagnetic semiconductors using static and time-resolved
Faraday rotation. The density, lifetime, and orientation rate of the
electrically-polarized spins are characterized by a combination of optical and
electrical methods. In addition, the dynamics of the current-induced spins are
investigated by utilizing electrical pulses generated from a photoconductive
switch. These results demonstrate the possibility of a spin source for
semiconductor spintronic devices without the use of magnetic materials.
