  The effect of an electric field on the spatial charge and spin profiles of
photoelectrons in p+-GaAs is studied as a function of lattice and electron
temperature. The charge and spin mobilities of photoelectrons are equal in all
conditions and exhibit the well known increase as the temperature is lowered.
It is shown that this is related mainly to the electron statistics rather than
the majority hole statistics. This finding suggests that current theoretical
models based on degeneracy of majority carriers cannot fully explain the
observed temperature dependence of minority carrier mobility.
