Copper Nanowires through Oriented Mesoporous Silica: A Step towards Protected and Parallel Atomic Switches

Abstract

The formation of copper atomic contacts has been investigated. Copper nanowires were grown by electrochemical deposition, in the scanning electrochemical microscopy (SECM) configuration, from a platinum microelectrode to an indium tin oxide (ITO) substrate. Self-termination leaves copper filaments between the two electrodes with an atomic point contact at the ITO electrode. Histogram analysis shows that the conductance of this contact is close to, or less than, 1 G0. Atomic contacts were also fabricated on ITO electrodes covered with vertically-aligned mesoporous silica films. Scanning Transmission Electron Microscopy images show that copper filaments occupy individual isolated nanopores. Contacts generated on bare ITO break down rapidly in sodium salicylate, whereas those generated in ITO/nanopores are unaffected; the nanopores protect the copper filaments. Finally, atomic switch behaviour was obtained using these ITO and ITO/nanopores electrodes.

Electroinduced Surfactant Self-Assembly Driven to Vertical Growth of Oriented Mesoporous Films

“…(D) Atomic switches: electrochemical deposition of individual copper nanowires through nanochannels and TEM imaging. Reproduced with permission from ref . Copyright 2017 Nature Publishing Group.…”

“…Porous membranes can basically be used as a hard template to grow arrays of nanowires or nanotubules of diameters typically in the 10−200 nm range. 50 However, if metal ions can be effectively reduced at EASA-film electrodes (with metal deposits detected by anodic stripping) 43 and if individual metal atomic contacts can be generated by local electrodeposition through such small-pore membranes, 51 the growth of mechanically stable metal nanowires remains restricted to pore diameters above 7 nm. 52 references cited therein), but diameters of the obtained polymeric nanostructures were larger (i.e., 5−30 nm) than the mesopore apertures (i.e., 2−3 nm), so that one can expect polymer growth out of the membrane or through film defects.…”

“…Atomic switches can be generated using an ultramicroelectrode tip from which metal nanowires can grow through single mesochannels (Figure 7D), leading to atomic contacts that are stabilized by the silica matrix. 51 Current rectification is achievable by exploiting the ionic strength effects at interfaces between two films of distinct surface charges. 56 The nanoconfinement of electron-donor-acceptor complexes 65 could be also appealing for molecular electronics.…”

Multi‐stimuli Photo and Redox‐active Nanostructured Mesoporous Silica Films on Transparent Electrodes

“…[28] In addition, the perfect 1D orientation of the nanochannels, whether they are oriented parallel or perpendicular to the supporting surface, can allow an alignment or 1D growth of anisotropic nanowires or nanorods, leading ultimately to a desired anisotropy in the resulting physical properties. [29][30][31][32][33][34] More recently, a composite mesoporous material based on Fe(Htrz) 3 @SiO 2 has been obtained in one pot, evidencing a template role of the spin crossover Fe(Htrz) 3 coordination polymer itself during the thin film growth. [35] The importance of having periodic ordered mesoporosity is highlighted for instance by the improved performance of Ru(bpy) 3containing silica nanocomposites for photovoltaic and chemiluminescence processes, resulting from an efficient charge transfer to the supporting electrode and better contacts with the hole-transporting electrolyte in such ordered materials.…”

Study of the surface structure of Fe quantum wire prepared by electrochemical method in solution

“…When the size of the materials and device is reduced to nanometer scale, many novel quantum phenomena will appear, which will bring many new and important applications [1][2][3]. A typical case is the quantum conductance behavior of the atomically thin metal junction, which has been verified with a large number of theoretical and experimental studies in the past decades [4][5][6].…”