Formation of a rectifier with gold nanoclusters: X-ray reflectivity and atomic force microscopy measurements

Abstract

We demonstrate that monolayer and bilayer films of thiol-capped gold nanoclusters can exhibit prominent rectification properties, provided spatial asymmetry exists between the two tunnel junctions used to connect the nanoclusters. Systematic X-ray reflectivity and atomic force microscopy (AFM) measurements were carried out to characterize the spatial asymmetry introduced by a monolayer of fatty acid salt used to deposit thiol-capped gold nanoclusters on a hydrophilic SiO₂-Si(001) substrate using the Langmuir-Blodgett technique. Current-voltage characteristics, obtained from conducting probe AFM measurements, show rectification ratios of 13.5 and 364.8 for the monolayer and bilayer films, respectively.