Influence of the nanostructure on the electric transport properties of resistive switching cluster-assembled gold films

The use of Au clusters produced in the gas phase and deposited at low kinetic energy on a substrate allows the bottom-up fabrication of nanostructured metallic thin films with an extremely large number of interfaces, grain boundary junctions and crystal lattice defects. Cluster-assembled gold films exhibit non-ohmic electrical transport properties with a complex resistive switching behavior, exploring discrete resistance states which depend on their structural features (average thickness, resistance value reached on the percolation curve). Their electric conduction properties can be modelled in terms of complex networks of nanojunctions and used to perform binary classification of Boolean functions. The fabrication of devices based on cluster-assembled Au films and exploiting emergent complexity and collective phenomena requires a deep understanding of the influence of the nanoscale structure on the fundamental mechanisms of electrical conduction. Here we present a detailed study of the correlation between the nanostructure and the electrical properties of cluster-assembled gold films by a systematic characterization of the film growth from sub-monolayer to continuous layer beyond the electrical percolation threshold. The influence of different cluster size distributions on the onset of the electrical conduction and the role of defects is investigated by combining in situ and ex situ electrical and structural characterizations.