  Electrical spin transport and accumulation have been measured in highly Si
doped Al0.3Ga0.7As utilizing a lateral spin transport device. Persistent
photoconductivity allows for the tuning of the effective carrier density of the
channel material in situ via photodoping. Hanle effect measurements are
completed at various carrier densities and the measurements yield spin
lifetimes on the order of nanoseconds, an order of magnitude smaller than in
bulk GaAs. These measurements illustrate that this methodology can be used to
obtain a detailed description of how spin lifetimes depend on carrier density
in semiconductors across the metal-insulator transition.
