  The effect of the electric field on the creation of spin 1/2 particles from
vacuum in the (1+1) dimensional de-Sitter space-time is studied. The Dirac
equation with a constant electric field is solved by introducing an unitary
transformation. Then the canonical method based on Bogoliubov transformation is
applied to calculate the pair creation probability and the density of created
particles both for positive or negative wave vector. By doing summation over
all allowed states, the number of created particles per unit of time per unit
of length and the imaginary part of the Schwinger effective action are
expressed in closed forms. It is shown that the electric field leads to a
significant enhancement of the particle creation. The weak expansion case and
the limit H=0, where dS space reduces to the flat Minkowski space-time, are
discussed.
