Electrical Properties of Hybrid Nanomembrane/Nanoparticle Heterojunctions: The Role of Inhomogeneous Arrays

Investigation of charge transport mechanisms across inhomogeneous nanoparticle (NP) layers in heterojunctions is one of the key technological challenges nowadays for developing novel hybrid nanostructured functional elements. Here, we successfully demonstrate for the first time the fabrication and characterization of a novel hybrid organic/inorganic heterojunction, which combines free-standing metallic nanomembranes with self-assembled mono- and sub-bilayers of commercially available colloidal NPs with no more than ∼105 NPs. The low-temperature conductance–voltage spectra exhibit Coulomb features that correlate with various interface’s configurations, including the presence of inhomogeneities at the nano- and micrometer scale owing to the NP size, the micrometer-sized voids, and the thickness of the layers. The charge transport features observed can be explained by a superposition of conductance characteristics of each individual type of NPs. The procedure adopted to fabricate the heterojunctions as well as the theoretical approach employed to study the charge transport mechanisms across the NP layers may be of interest for investigating different types of NPs and commonly obtained inhomogeneous layers. In addition, the combination of metallic nanomembranes with self-assembled layers of NPs makes such a hybrid organic/inorganic heterostructure an interesting platform and building block for future nanoelectronics, especially after intentional tuning of its electronic behavior.