Quasimetallic behavior of carrier-polarized C60 molecular layers:: Experiment and theory -: art. no. 155440

Although C-60 is an insulator with a band gap E-g of similar to 2.5 eV, we show experimentally and theoretically that E-g is strongly affected by image forces and injected charges. In sharp contrast to the Coulomb blockade typical of quantum dots, E-g is reduced by Coulomb effects. The conductance of a micron-sized C-60 film sandwiched between metal (Al, Ag, Au, Mg, and Pt) contacts is investigated. Excellent Ohmic conductance holds for C-60 layers at room temperature, on using Al/LiF bilayer contacts. Arrhenius type activated conductivity with an activation gap of similar to 0.16 eV is found.