The Electrical Measurement of Molecular Junctions

Publisher Website
Google Scholar
Abstract
We present the investigation of the electrical transport of metal/(organic molecule or monolayer)/metal junctions. Utilizing a novel mechanically controllable break junction to form a statically stable system, we have self‐assembled molecules of benzene‐ 1,4‐dithiol onto two facing gold electrodes allowing for direct observation of charge transport through the molecules. Current‐voltage I(V) measurements provides a quantitative measure of the conductance of a junction containing a single molecule. We have also created a technique to form well‐defined, stable, and reproducible metallic contacts to a self‐assembled monolayer of 4‐thioacetylbiphenyl with nanoscale area. Electronic transport measurements show a prominent rectifying behavior arising from the asymmetry of the molecular heterostructure. Variable‐temperature measurements reveal the dominant transport mechanisms, such as thermionic emission for the Ti‐organic system. These techniques demonstrate the capability of electrically characterizing and engineering conductive molecular systems for future potential device applications.