Charge transport in conjugated organic oligomers: Anodic stripping voltammetry and nanostructured array electrodes

One of the goals of nanotechnology is the fabrication of nanometer-sized components for molecular electronics. Conjugated organic oligomers have been proposed as molecular wires which will serve to interconnect hypothetical nanoscale electronics devices. However, very little is known about the electronic characteristics of these oligomers with respect to connections made to real materials.; We have developed a technique for measuring charge transport through self-assembled monolayers (SAMs) of conjugated oligomers. Electrodes were prepared with SAMs of the conjugated oligomers on gold electrodes and overcoated with copper metal to create metal—organic—metal junctions. Both electrochemical deposition and physical vapor deposition were explored for the metal coating. Anodic stripping voltammetry was then used to remove defects where the copper was shorted to the gold and to oxidize the copper with electron transport through the conjugated oligomers. From this data, the barrier to charge injection from the metal contacts was calculated.; These experiments depended on the integrity of the monolayer following metal coating. In order to characterize the structure of the monolayer following metal coating, electrochemical passivation, x-ray photoelectron spectroscopy, and grazing—angle infrared spectroscopy experiments were performed on alkanethiol self-assembled monolayers on gold electrodes.; This technique only provides data at limited potentials since it relies on the oxidation of a metal for the collection of data. The remaining copper particles after defect removal were too small to make electrical contact with. In order to collect the full current—voltage data, nanowell array electrodes have been fabricated which may permit macroscopic connections to both metal layers in the metal—organic—metal junction. Electroplating of gold to fill the pores of an Anodisc filtration membrane, which was used as a template, followed by polishing was performed prior to generation of wells by electrochemical gold stripping, ion bombardment, or a combination of both ion bombardment and electrochemical gold stripping.