We calculate the conductance through double junctions of the type M(inf.)-Sn-Mm-Sn-M(inf.) and triple junctions of the type M(inf.)-Sn-Mm-Sn-Mm-Sn-M(inf.), where M(inf.) are semi-infinite metallic electrodes, Sn are n layers of semiconductor and Mm are m layers of metal (the same as the electrodes), and compare the results with the conductance through simple junctions of the type M(inf.)-Sn-M(inf.). The junctions are bi-dimensional and their parts (electrodes and active region) are periodic in the direction perpendicular to the transport direction. To calculate the conductance we use the Greens Functions Landauer-B$ddot{u}$ttiker formalism. The electronic structure of the junction is modeled by a tight binding Hamiltonian. For a simple junction we find that the conductance decays exponentially with semiconductor thickness. For double and triple junctions, the conductance oscillates with the metal in-between thickness, and presents peaks for which the conductance is enhanced by 1-4 orders of magnitude. We find that when there is a conductance peak, the conductance is higher to that corresponding to a simple junction. The maximum ratio between the conductance of a double junction and the conductance of a simple junction is 146 %, while for a triple junction it is 323 %. These oscillations in the conductance are explained in terms of the energy spectrum of the junctions active region.
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