Electrical properties of self-organized nanostructures of alkanethiol-encapsulated gold particles

In this article, we present the fabrication and electrical characterization of nanostructures made of alkanethiol-encapsulated gold particles. We fabricated ordered close-packed monolayer and multilayer structures of encapsulated gold particles using a self-organization process. Room-temperature electrical properties of these nanostructures were studied by using a conductive atomic force microscope. In both cases of monolayer and multilayer structures, the current suppression around zero bias was observed for 9-nm-diameter gold particles. However, it was not observed for 20-nm-diameter particles. This suggests that the Coulomb blockade has occurred in the case of 9-nm-diameter particles. Moreover, the current–voltage properties of multilayer structures demonstrate a nearly linear relation between the Coulomb gap Vg and the number of layers NL, which is in good agreement with the theory of single-electron tunneling in a tunnel-junction array. These electrical properties suggest that an alkanethiol shell on gold particles can serve as a stable tunnel barrier. As a consequence, the proposed method for fabricating quantum dot structures is very useful for developing nanoelectronic devices.