Conductance of Single Cobalt Chalcogenide Cluster Junctions

Abstract

Understanding the electrical properties of semiconducting quantum dot devices have been limited due to the variability of their size/composition and the chemistry of ligand/electrode binding. Furthermore, to probe their electrical conduction properties and its dependence on ligand/electrode binding, measurements must be carried out at the single dot/cluster level. Herein we report scanning tunneling microscope based break junction measurements of cobalt chalcogenide clusters with Te, Se and S to probe the conductance properties. Our measured conductance trends show that the Co-Te based clusters have the highest conductance while the Co-S clusters the lowest. These trends are in very good agreement with cyclic voltammetry measurements of the first oxidation potentials and with density functional theory calculations of their HOMO-LUMO gaps.

Inorganic and Organometallic Molecular Wires for Single‐Molecule Devices

“…Metal calcogenide clusters with spherical shapes 12 are also an interesting class of compounds as molecular devices due to their robustness and good solubility. Venkataraman, Steigerwald, and Nuckolls reported single‐molecule conductance of cobalt derivatives ( 12 X : Co 6 (μ 3 ‐X) 8 (PEt 3 ) 6 , in which X=S, Se and Te; Figure b), which interacted with Au electrodes through X–Au interactions . The conductance peaks were rather broadened due to the presence of two different contact modes ( cis and trans ).…”

Solvent-dependent conductance decay constants in single cluster junctions

“…While numerous organic molecules have been studied as connecting wires for single-molecule junction studies,3–10 very little is known about the effect of metal complexes in these types of junctions 11–14. We recently reported that we could incorporate metal chalcogenide molecular clusters in single-molecule electrical circuits 15.…”

Conformation‐Controlled Electron Transport in Single‐Molecule Junctions Containing Oligo(phenylene ethynylene) Derivatives

“…With the development of measuring techniques, it is now possible to integrate single molecules into electronic circuits and to measure their electron-transport properties in a variety of experimental setups, including mechanically controlled break junctions (MCBJ), [2] electromigration, [3] and break junctions based on scanning tunneling microscopy (STM). [4] STM break junctions [4] have been established as a reliable technique for investigating correlations between molecular structures and transport properties on a single-molecule level, which has been successfully employed to investigate electron transport through junctions that contain various molecules, including alkanethiol, [5] organometallic complexes, [6] semiconductor clusters, [7] oligofluorene, [8] oligothiophene, [9] and porphyrin-fullerene complexes. [10] Recently, this technique has been used to study the conductance through more complicated systems.…”