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We explored the modification of polymeric film conductivity by changing the conducting filler percentage in the frame of the percolation theory. The polymeric film is a polystyrene (PS) matrix, while the fillers are gold nanoparticles capped with 1‐dodecanethiol (Au‐DT NPs) and small conjugated molecules 8‐ hydroxyquinoline (8HQ). Experimental results show, that increasing the Au‐ DT and 8HQ wt%, film conductivity increases by up to three orders of magnitude due to charge transfer in the 3D network composed by Au‐ DT NPs and 8HQ.

Three-terminal superconducting tunnel devices offer a powerful tool to investigate nonequilibrium phenomena in superconductors. We study the role of the proximity effect in a Nb/Al bilayer forming the intermediate electrode of a stacked structure configuration. The spatial profile of the pair potential along the common electrode and the effective density of states near the detector tunnel barrier are determined by combining the deconvolution of the current-voltage (I-V) injector characteristics and the numerical solution of the microscopic proximity model equations. The Josephson current variation following a steady-state injection was measured down to 1.5 K. Results are discussed in the framework of a simple nonequilibrium model, which leads also to an estimate of the effective relaxation time limiting quasiparticle scattering processes in the Nb/Al bilayer.

Today’s lithographic techniques for carving silicon into circuit patterns are unable to achieve the future target of the semiconductor industry of fabricating ultrahigh density memory devices made of memory cells just few tens of nanometers apart. Methods of extending these approaches to large-scale, high-density circuitry are largely undeveloped. Between emerging self-assembly bottom-up methods for advanced fabrication of electronic devices based on organic matrices, nanocomposites formed by a conducting phase (e.g. metal nanoparticles) dispersed in a polymeric matrix have attracted considerable attention, because these materials might be used as an active layer in almost all kinds of organic electronic devices. In this paper a different approach for the fabrication of advanced electronic devices is suggested, based on the combination of two concepts: the use of organic materials as active layers that guarantees simplified manufacturing process yielding low-cost, flexible, and light-weight devices, and the use of self-assembly of block copolymers (BCPs) that allows building nanostructures from the bottom up using individual macromolecules. The ordered cylindrical self-assembled nanostructure formed from PS- b -PMMA is used as host for selectively sequestering gold nanoparticles. The ordered distribution of the functional particles is guided by the ordering of the host matrix and allows arising other numerous possible applications that depend on the nanospecific properties of the sequestered components and the intrinsic flexibility of the polymeric matrix. The BCP structure has many considerable advantages in terms of low material consumptions and reduced operating voltages for producing high bistability effects in well ordered nanostructures. Moreover, the excellent results we achieved in terms of electronic performances and the high potential opened by this nanotechnology toward the development of innovative materials open the way toward the realization of novel organic devices containing different physical types of functionalized nanoparticles (e.g. oxides, superconductors, etc.), and the investigation of their fundamental properties.

A new fabrication process for three-terminal superconducting devices consisting of two Josephson junctions in a stacked configuration is reported. The process is based on the deposition of the whole Nb/AlxOy/Nb-Al/AlxOy/Nb multilayer on a Si crystalline wafer without any vacuum breaking. Lift-off techniques, anodization processes and a SiO film deposition have been adopted for patterning and insulating the two tunnel stacked junctions. Devices have been characterized in terms of current-voltage (I-V) curves and Josephson critical current vs. the externally applied magnetic field. They show high quality factors (V m values up to 65 mV at 4.2 K), and good current uniformity.

The analysis of the electrical properties of polystyrene films containing gold nanoparticles capped with 1-dodecanethiol and 8-hydroxyquinoline molecules is reported. The conductivity of the nanocomposite as a function of the doping level has been investigated both in planar and stacked configurations. While the former configuration evidenced low field tunneling between nanoparticles in the polymer matrix, stacked devices allowed us to investigate the main phenomena ruling the transport properties when switching effects are present close to critical electric fields. In particular, through the analysis of current-voltage characteristics we studied the charge transport at different fillers concentrations and sketched a physical picture of conductivity in such nanocomposite systems.