Fabrication and Electrical Characterization of Tetrathiafulvalene-tetracyanoquinodimethane Molecular Wires

We have fabricated tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) molecular wires between a parallel cathode and anode (100 µm electrode gap) using the co-evaporation technique with an applied electric field. Wire-shaped microcrystals of TTF-TCNQ grew along the electric field. We have succeeded in fabricating connected wires with an optimum applied voltage. A narrow-gap (20 µm) electrode was used to grow wires with a low applied voltage, which make it possible to fabricate the connected wires easily. The measured I-V curve indicated Ohmic contact between the gold electrode and TTF-TCNQ. Semiconductor-like conduction of the fabricated TTF-TCNQ sample was shown by the temperature dependence of conductivity. Some of the co-evaporated TTF-TCNQ wires may tend to be semiconducting due to nonstoichiometry of TTF1-δ-TCNQ1.