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

Abstract

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.

Single-molecule electronics: from chemical design to functional devices

“…Ruitenbeek et al then carried out shot noise measurements on the Pt-D 2 -Pt junction formed by the MCBJ technique, and the observed quantum suppression indicated that the junction was indeed formed by just a single molecule. 45,[79][80][81][82][83] …”

“…77 With similar nanoparticle-molecule-nanoparticle bridge structures, Parsons et al investigated the conduction mechanisms and stability of single OPE (oligo(p-phenylene ethylenes)) molecules. 79 Furthermore, Jain et al reported a strategy to fabricate 1-2 nm nanogaps via seed-mediated growth of end-to-end linked gold nanorods (AuNRs). 80 Mayor et al demonstrated that the interparticle distance of gold nanoparticle dimers could be controllable by an atomic alteration in the structure of the linker molecule.…”

Dielectrophoresis at the nanoscale

“…A different approach was used by groups of Bar-Joseph [42] (see Fig. 2B) and Parsons [43]. These groups synthesized a dimmer structure, consisting of two colloidal gold particles connected by short organic molecules.…”

“…These groups synthesized a dimmer structure, consisting of two colloidal gold particles connected by short organic molecules. Then, either dc [42] or ac [43] DEP was used to place dimmers between prefabricated electrodes. Yao and co-workers reported fabrication of a single electron transistor using dielectrophoretic trapping of individual gold NPs [44].…”

Controlling the concentration of gold nanorods during their dielectrophoresis-assisted deposition

“…Moreover, the frequency dependence of DEP, which gives rise to other processes such as electro-osmotic and electro-thermal flows, has been shown to affect the deposition of NPs between the electrodes [24][25][26]. Such advances in DEP resulted in the successful bridging of NPs in the electrodes gap [27][28][29].…”