Measurement of Single-Molecule Resistance by Repeated Formation of Molecular Junctions

• Published in: Science (American Association for the Advancement of Science) Vol. 301; no. 5637; pp. 1221 - 1223
• Main Authors: Xu, Bingqian, Tao, Nongjian J.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 29-08-2003; The American Association for the Advancement of Science
• Subjects: Atoms; Biological and medical sciences; Carbenes; Chemistry; Electric current; Electric potential; Electric properties; Electric resistance; Electrical resistance; Electrodes; Electrons; Fundamental and applied biological sciences. Psychology; General aspects; Gold; Histograms; Laboratory Equipment; Molecular biophysics; Molecules; Numbers; Precious metal products; Statistical Analysis; Thiols; Resistance; Molecules; Junction; Molecular structure; Mechanical characteristic
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1087481

The conductance of a single molecule connected to two gold electrodes was determined by repeatedly forming thousands of gold-molecule-gold junctions. Conductance histograms revealed well-defined peaks at integer multiples of a fundamental conductance value, which was used to identify the conductance of a single molecule. The resistances near zero bias were$10.5 \pm 0.5$,$51 \pm 5$,$630 \pm 50$, and$1.3 \pm 0.1$megohms for hexanedithiol, octanedithiol, decanedithiol, and 4,4' bipyridine, respectively. The tunneling decay constant (βN) for N-alkanedithiols was$1.0 \pm 0.1$per carbon atom and was weakly dependent on the applied bias. The resistance and βNvalues are consistent with first-principles calculations.