Tunneling rates in electron transport through double-barrier molecular junctions in a scanning tunneling microscope
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- G. V. Nazin
- Departments of Physics & Astronomy and Chemistry, University of California, Irvine, CA 92697-4575
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- S. W. Wu
- Departments of Physics & Astronomy and Chemistry, University of California, Irvine, CA 92697-4575
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- W. Ho
- Departments of Physics & Astronomy and Chemistry, University of California, Irvine, CA 92697-4575
抄録
<jats:p>The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends.</jats:p>
収録刊行物
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- Proceedings of the National Academy of Sciences
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Proceedings of the National Academy of Sciences 102 (25), 8832-8837, 2005-06-14
Proceedings of the National Academy of Sciences