Tuning the Tunneling Rate and Dielectric Response of SAM-Based Junctions via a Single Polarizable Atom.

The dielectric response and electrical properties of junctions based on self-assembled monolayers (SAMs) of the form S(CH2)11X can be controlled by changing the polarizability of X (here X = H, F, Cl, Br, or I). A 1000-fold increase in the tunneling rate and a four-fold increase of the dielectric constant (ε r ) with increasing polarizability of X are found.