Inelastic electron tunneling spectroscopy of single-molecule junctions using a mechanically controllable break junction

摘要

We report the use of electrical measurements to identify simultaneously the number and type oforganic molecules within metal—molecule—metal junctions. Our strategy combines analyses ofsingle-molecule conductance and inelastic electron tunneling spectra, exploiting ananofabricated mechanically controllable break junction. We found that the peak linewidth ofthe inelastic electron tunneling spectrum decreased as the modulation voltage and temperaturedecreased, and that the selection rule for inelastic electron tunneling spectroscopy agrees withthat for Raman spectroscopy. Furthermore, the differential conductance curve of thesingle-molecule junction suggests that it has asymmetrical electrode—molecule coupling.