  The problem of spin-dependent transport of electrons through a finite array
of quantum dots attached to 1D quantum wire (spin gun) for various
semiconductor materials is studied. Unlike the model considered in [1] a model
proposed here is based on the extension theory model (ETM) and assumes the
quantum dots to have an arbitrary internal structure, i.e. the internal energy
levels. The presence of internal structure in quantum dots results in
energy-dependent interaction between electrons and quantum dots. This
interaction changes the transmission mode of the spin current through the spin
gun. For the energy-dependent interaction it is shown in this article the
difference of transmission probabilities for singlet and triplet channels for
several quantum dots in the array due to interference effects can reach
approximately 100% percent for some energy intervals. For the same energy
intervals the conductance of the device reaches the value in units. As a result
a model of the spin-gun which transforms the spin unpolarized electron beam
into completely polarized one is suggested.
