Song Hyunwook

Single molecule electronic devices in which individual molecules are utilized as active electronic components constitute a promising approach for the ultimate miniaturization and integration of electronic devices in nanotechnology through the bottom-up strategy. Thus, the ability to understand, control, and exploit charge transport at the level of single molecules has become a long-standing desire of scientists and engineers from different disciplines for various potential device applications. I

Intermolecular chain-to-chain tunneling in metal−alkanethiol−metal junctions was investigated by measuring the molecular-tilt dependence of the tunneling through a molecular ensemble of alkanethiols using conducting atomic force microscopy. A variable tip-loading force was applied to tilt the molecular configuration while measuring the current−voltage characteristics of the molecular junctions. The observed transport through the molecules exhibited a tilt angle dependent intermolecular charge tr

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 e

We measure the vibrational signatures of metal-molecule-metal junctions formed from 1,8-octanedithiol and 1,4-benzenedithiol incorporated into electromigrated nanogap electrodes using inelastic electron tunneling spectroscopy (IETS). The junction conductance measured suggests that the IETS spectra have been achieved at the individual molecule level. The IETS spectra provide unambiguous experimental evidence of the existence of the component molecules in the fabricated nanogap electrode testbeds.

We present the measurement of charge transport through phenylene conjugated molecules using electromigrated nanogap junctions. To elucidate the intrinsic transport properties of the conjugated molecular junctions, a variety of molecular transport techniques were performed at low temperature, including inelastic electron tunneling spectroscopy, temperature- and length-variable transport measurements, and transition voltage spectroscopy. Such a self-consistent characterization of the molecular jun

We present a statistical method to investigate the electronic transport of molecular devices. Electrical characterizations are performed with subsequent statistical analysis on 6745 molecular devices with nanometer-scale junction diameter. The comprehensive temperature-variable current-voltage measurements are also performed to elucidate the dominant charge conduction mechanism responsible for intrinsic molecular transport properties. The entity of data acquired represents a reliable basis for s

Over the past few decades, the field of molecular electronics has greatly benefited from advances in the fundamental understanding of charge transport mechanisms. Molecular junctions represent a field whose potential is realized through detailed studies of charge transport on the nanoscale. Applications of molecular junctions, such as molecular logic circuits, rely on precise mechanistic information as investigative techniques are refined. Current advances have originated from improvements in a

Molecular junctions in which individual molecules are utilized as active electronic components constitute a promising approach for the ultimate miniaturization and integration of electronic devices through the bottom-up strategy. A study on charge transport through the constituent molecules attached to two metallic electrodes is a very challenging task, but advances have been made in recent years. Especially, inelastic electron tunneling spectroscopy (IETS) has recently become a premier analytic

The field of molecular electronics is prompted by tremendous opportunities for using a single-molecule and molecular monolayers as active components in integrated circuits. Until now, a wide range of molecular devices exhibiting characteristic functions, such as diodes, transistors, switches, and memory, have been demonstrated. However, a full understanding of the crucial factors that affect charge transport through molecular electronic junctions should yet be accomplished. Remarkably, recent ad