Jennifer Ayres

Conduction mechanisms and stability of single molecule nanoparticle/molecule/ nanoparticle junctions

Nanoparticle/molecule/nanoparticle dimer assemblies have been successfully trapped by dielectrophoresis across nanogap electrodes, enabling temperature dependent charge transport measurements through an oligomeric phenylene ethynylene molecule, and transition from direct tunnelling to Fowler-Nordheim tunnelling is observed at approximately 1.5 V. Samples formed by dielectrophoresis show better contact stability than those formed by receding meniscus. The junction shows stable operation over several weeks in a vacuum, but current increases with time upon exposure to air, possibly due to the adsorbed water molecules near the molecule/gold nanoparticle contacts.

Hierarchical Assembly for Molecular Electronics

Miniaturizing electronic devices to the molecular scale is the next major step in the electronics revolution. To do this, however, three major unsolved challenges must be overcome. These are: (1) Synthesis of new molecules with functionality that allows them to act as nonlinear electronic elements and to attach them in a specific orientation to contact structures (2) Bridging the molecular (created via bottom-up fabrication) with the lithographic (created via top- down fabrication) length scales for device construction and (3) definition of new lithographic approaches that accommodate molecular installation during processing. Here, an approach and its implementation will be discussed that addresses each of these issues. In addition, the approach is designed to facilitate the demonstration of gain at the molecular level which can result from a state change within the molecular architecture rather than as the response of a molecule to a change in bias of an underlying (macroscopic) gate electrode.