Negative differential resistance in a bilayer molecular junction

Negative differential resistance (NDR) is reported for a bilayer molecular junction. The system is comprised of a Hg–alkanethiol//arenethiol–Au bilayer molecular junction formed by bringing into contact a tetradecanethiol self-assembled monolayer (SAM)-coated drop of Hg with the surface of an oligo(phenylene-ethynylene) SAM on Au. Persistent, reproducible NDR is observed in the current–voltage characteristics with peak-to-valley ratios as high as 4.5 at room temperature. These results open a promising line of investigation of structure/function relationship and mechanisms in molecular NDR components.