Characterization of periodically nanostructured copper filaments self-organized by electrodeposition

Abstract

We report in this paper the electric properties of nanostructured copper filament arrays self-organized by a novel electrochemical method. Due to the spontaneous oscillation of the concentration field of [Cu2+ ] in front of the growing interface, crystallites of copper and cuprous oxide appear alternately on the filaments of the electrodeposits. A conducting atomic force microscope (CAFM) and current imaging tunnelling spectroscopy (CITS) were used to characterize the electric properties of the nanostructured copper filaments. By applying a constant voltage across the conducting probe of the CAFM and the sample, an electric current mapping is achieved, in which alternating low and high current regions correspond exactly to the periodic nanostructures on the filaments. The profile of the electric current along the structured filament has been analysed, and no noticeable potential drop has been observed. A typical linear I–V curve for a metal and nonlinear I–V curve for a semiconductor were collected in the high and low current regions respectively. These results suggest that despite the periodic distribution of Cu2O crystallites on the deposited filament, there should exist a metallic core of copper crystallites inside the filament. This type of structured metal–semiconductor filament might have potential application.

Electrodeposition of submicron/nanoscale Cu2O/Cu junctions in an ultrathin CuSO4 solution layer

“…5a shows the AFM image of sample and all the measuring points located at the ACs or the NCs. In this measurement, the CAFM's probe with the coating of Pt-Ir alloy contacted to the Cu 2 O grains, thus the measuring circuit is mainly formed by the metallic CAFM's probe, the semiconducting Cu 2 O grain and the main body of electrodeposit in which the Cu crystallites can provide a conductive path [32]. Such probe/Cu 2 O/ Cu structure can be regarded as the two metal/semiconductor junctions connected inversely.…”

“…The electric properties of electrodeposited filaments were characterized by conducting atomic force microscopy (CAFM). The result indicated that the Cu 2 O crystallites may be more concentrated in the concave region of the periodic corrugated nanostructures and the filament has a metallic core formed by copper crystallites [32]. Pattern selection of electrodeposits at micron and submicron scale has been studied under different growth driving forces [33].…”

Propagation Along Single-Crystalline Silver Filaments With Pearl-Chain-Like Structures

“…When the electromagnetic wave propagates along metallic filaments, scattering is evident at positions where branching occurs. Previous works have demonstrated that ramification of Cu filaments can be greatly reduced with the unique electrodepositon method [13,14,16]. Comparing to silver dendrites [20] and silver fractal structures [21], ramification of these silver filaments with pearl-chain-like structures is also greatly reduced with this unique eletrodeposition method [17].…”

“…An electrodeposition system [13][14][15][16][17] is exploited to fabricate microstructure single-crystalline silver filaments without using any templates, surfactants, and additives. The experimental details are analogous to previous works [13][14][15][16][17].…”

“…The experimental details are analogous to previous works [13][14][15][16][17]. AgNO 3 aqueous electrolyte is prepared by dissolving AgNO 3 (analytically pure, 99.8%) with deionized ultrapure water (Millipore, electric resistivity of 18.2 MΩ·cm) and the concentration is 0.05 M. Parallel, straight electrodes are made of pure silver wires (99.99% pure, 0.5 mm in diameter, Goodfellow), and sandwiched by two glass slides.…”