We have theoretically investigated the electronic structure of Si delta -do
ped GaAs inserted into a quantum well under an applied electric field. For
uniform distribution we have studied the influence of the electric field on
the donor concentration. The electronic properties such as the effective p
otential. the density profile, the subband energies, the subband occupation
s and the Fermi energy level have been calculated by solving the Schrodinge
r and Poisson equations self-consistently. From our calculations, we have s
een that the change of the electronic properties as dependent on the applie
d electric field is more pronounced at low doping concentration. The high e
lectric fields can induce a spatial separation between confined electrons a
nd ionized dopants in the delta -doped GaAs structure, resulting in enhance
d free-carrier mobility in devices.