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Inelastic electron tunneling spectroscopy (IETS) of an alkanedithiol self-assembled monolayer (SAM) is investigated using a nanometer-scale device. The IETS spectrum of the octanedithiol device clearly shows vibrational signatures of an octanedithiolate, −SC 8 H 16 S−, bonded to gold electrodes. The pronounced IETS peaks correspond to vibrational modes perpendicular to the junction interface, which include the stretching modes of Au−S (at 33 mV) and C−C (at 133 mV) and the wagging mode of CH 2 (at 158 mV). The observed peak intensities and peak widths are in good agreement with theoretical predictions.

Presented here are several convergent synthetic routes to conjugated oligo(phenylene ethynylene)s. Some of these oligomers are free of functional groups, while others possess donor groups, acceptor groups, porphyrin interiors, and other heterocyclic interiors for various potential transmission and digital device applications. The syntheses of oligo(phenylene ethynylene)s with a variety of end groups for attachment to numerous metal probes and surfaces are presented. Some of the functionalized molecular systems showed linear, wire-like, current versus voltage (I(V)) responses, while others exhibited nonlinear I(V) curves for negative differential resistance (NDR) and molecular random access memory effects. Finally, the syntheses of functionalized oligomers are described that can form self-assembled monolayers on metallic electrodes that reduce the Schottky barriers. Information from the Schottky barrier studies can provide useful insight into molecular alligator clip optimizations for molecular electronics.

A review of the mechanisms and characterization methods of molecular electronic transport is presented. Using self-assembled monolayers (SAMs) of alkanethiols in a nanometer-scale device structure, tunneling is unambiguously demonstrated to be the main conduction mechanism for large band gap SAMs exhibiting well-known temperature and length dependencies. Inelastic electron tunneling spectroscopy exhibits clear vibrational modes of the molecules in the device, presenting the first direct evidence of the presence of molecules in a molecular transport device and confirming the tunneling transport mechanism in alkane self-assembled monolayers.

A review on the mechanisms and characterization methods of electronic transport through self-assembled monolayers (SAMs) is presented. Using SAMs of alkanethiols in a nanometre scale device structure, tunnelling is unambiguously demonstrated as the main intrinsic conduction mechanism for defect-free large bandgap SAMs, exhibiting well-known temperature and length dependences. Inelastic electron tunnelling spectroscopy exhibits clear vibrational modes of the molecules in the device, presenting direct evidence of the presence of molecules in the device.