Symmetric Large-Area Metal-Molecular Monolayer-Metal Junctions by Wedging Transfer

A method is described for fabricating and electrically characterizing large-area (100–400 μm2) metal-molecular monolayer-metal junctions with a relatively high overall yield of ≈45%. The measurement geometry consists of ultra-smooth (template-stripped) patterned Au bottom electrodes, combined with ultra-smooth top Au electrodes deposited using wedging transfer. The fabrication method is applied to the electrical characterization of Au-alkanethiol self-assembled monolayer-Au junctions. An exponential decay of the current density is found for increasing the chain length of the alkanethiols, in agreement with earlier studies. The symmetric device geometry, and flexibility for contacting monolayers with various end groups are important advantages compared to existing techniques for electrically characterizing molecular monolayers.