Noise Characteristics of Charge Tunneling via Localized States in Metal−Molecule−Metal Junctions

We report the noise characteristics of charge transport through an alkyl-based metal--molecule--metal junction. Measurements of the 1/f noise, random telegraph noise, and shot noise demonstrated the existence of localized traps in the molecular junctions. These three noise measurements exhibited results consistent with trap-mediated tunneling activated over approximately 0.4 V by trapping and detrapping processes via localized states (or defects). The noise characterizations will be useful in evaluating the influences of localized states on charge transport in molecular or other electronic junctions.