Coherent Tunneling Transport in Molecular Junctions

Using saturated alkyl chain series with a dithiol anchor group, we systematically examined the intrinsic charge transport of single-molecule junctions in an electromigrated nanogap electrode. The saturated alkyl molecular system constitutes an important control series in molecular transport experiments to corroborate valid molecular junctions, because molecular energy levels remain nearly unchanged with molecular length, and the transport mechanism has been unambiguously established. Inelastic electron tunneling spectroscopy, temperature-variable current−voltage measurement, length-dependent conductance measurement, and transition voltage spectroscopy all validate the observation of intrinsic molecular properties in the electromigrated nanogap junctions.