  The dependence of the transport properties on the specific location of the
Fermi level in molecular electronics devices is studied by using electrodes of
different materials. The zero-bias transport properties are shown to depend
dramatically on the elemental composition of the electrodes, even though the
shape of the transmission coefficients is very similar. By using alkaline
materials it is possible to move the Fermi level from the HOMO-LUMO gap to the
LUMO resonance and change dramatically the length dependence of the conductance
of molecular wires, which opens the possibility of using molecules with
different lengths and very similar conductances in nanoscale circuits. This
method shows how to dramatically increase the conductance of molecular devices
and alter qualitatively and quantitatively their electronic and transport
properties.
