In this work, Milano et al. reported on quantum conductance effects in memristive nanowires, unveiling the origin of deviations of conductance levels from integer multiples of the conductance quantum and analyzing conductance fluctuations over time of memristive devices.

Copper oxide nanowires (NWs) are promising elements for the realization of a wide range of devices for low-power electronics, gas sensors, and energy storage applications, due to their high aspect ratio, low environmental impact, and cost-effective manufacturing. Here, we report on the electrical and thermal properties of copper oxide NWs synthetized through thermal growth directly on copper foil. Structural characterization revealed that the growth process resulted in the formation of vertically aligned NWs on the Cu growth substrate, while the investigation of chemical composition revealed that the NWs were composed of CuO rather than Cu₂O. The electrical characterization of single-NW-based devices, in which single NWs were contacted by Cu electrodes, revealed that the NWs were characterized by a conductivity of 7.6 × 10⁻² S∙cm⁻¹. The effect of the metal–insulator interface at the NW–electrode contact was analyzed by comparing characterizations in two-terminal and four-terminal configurations. The effective thermal conductivity of single CuO NWs placed on a substrate was measured using Scanning Thermal Microscopy (SThM), providing a value of 2.6 W∙m⁻¹∙K⁻¹, and using a simple Finite Difference model, an estimate for the thermal conductivity of the nanowire itself was obtained as 3.1 W∙m⁻¹∙K⁻¹. By shedding new light on the electrical and thermal properties of single CuO NWs, these results can be exploited for the rational design of a wide range of optoelectronic devices based on NWs.

A thorough investigation of quantum conductance properties and the effects of temperature on $\text{Cr/Au/TiO}_{\text{2}}/\text{TiO}_{\textit{x}}\text{/Cr/Au}$ memristive devices is presented. Besides fabrication and resistive switching characteristics, two different programming strategies have been explored to observe quantum conductance effects. The first strategy was based on device stimulation with slow current sweeps to observe quantum levels in the SET region, while the second aimed to achieve quantum steps during RESET using slow sweep stimulation. The effects of the two different programming strategies are compared. It is also shown that these devices can be programed to achieve stable quantum levels, as revealed by retention measurements performed after programming the device to 1 $\textit{G}_\text{0}$ . Furthermore, the temperature-dependent electronic conduction mechanism of the device after being programed to different internal resistance states has been analyzed, revealing a semiconductor behavior with an increase in resistance by lowering the temperature in either a pristine state, low-resistance state, or resistance states close to the quantum conduction regime.

Silicon nanowires (NWs) with a cylindrical form are fabricated by means of nanosphere lithography and metal-assisted chemical etching to obtain high aspect ratio nanostructures (diameter of about 100 nm and length of more than 15 µm) on an approximately 1 cm² area. The nanodimensional characterization of individual NWs is performed by using several techniques, because dimensions at the nanoscale strictly relate to functional performance. In this study, we report the results of an interlaboratory comparison between measurements from a metrological atomic force microscope (AFM) and research AFMs located in different national metrology institutes (NMIs) across Europe and in a university. The purpose of this study is to characterize two measurands: (i) sidewall roughness ( R a , R q , R z , R sk , R ku parameters) extracted from the top profile measured along the nanowire length, and (ii) diameter of the nanowires measured as top-height. To this goal, the nanowires are spread horizontally on a silicon substrate, which has several areas labelled with a pattern of crosses and letters facilitating the measurement of the same NW, in order to study the reproducibility due to different instruments. Measurements show a good agreement between the different NMIs, with a combined standard uncertainty of top-height diameter less than 3%, and with a combined standard uncertainty of roughness parameters well within 5% for R a and R q values.

Electrical transport in single nanowire (NW) devices arises from the interplay between intrinsic conduction properties of the NW and the transport characteristics of metal-semiconductor contact interfaces. Here, we present a framework for the quantitative analysis of current–voltage–temperature ( I–V–T ) characteristics of metal-oxide NWs. By analyzing experimental data obtained from a nanodevice based on a single CuO NW contacted by metal electrodes, we show that single-NW devices can be described using a metal–semiconductor–metal (M–S–M) transport model that accounts for thermionic emission and thermionic-field emission at Schottky metal-semiconductor interfaces. Through numerical implementation, we show that the M–S–M model distinguishes the electrical transport contributions of the NW from those of the two metal-semiconductor interfaces, enabling the extraction of the temperature-dependent NW resistance and activation energy. The effective interface parameters further provide qualitative insight into the non-ideal contact transport. Comparison with the commonly used large-bias approximation allows us to assess the validity and limitations of this simplified extraction method, while providing an independent cross-check of the quality of the M–S–M transport model. Overall, the proposed approach provides a general framework for disentangling intrinsic NW conduction from contact effects in temperature-dependent two-terminal measurements of single-NW semiconductor devices.

Recently, superconducting nanostructures gained particular attention due to the visualisation of some intriguing phenomena, such as phase fluctuations, quantum phase slip, shape resonance in critical temperature, allowing the definition of a tailored superconducting nanodevice with the desired superconducting features, quantum phenomena. A deep investigation into the relationship between superconductivity, low dimensionality, quantum phenomena should be performed, in order to explain the emergence mechanism of these effects in nanostructures, how superconductivity is affected. In the following, we report on the investigation of the superconductive transition in triangular-shaped Nb pads connecting a Nb nanostripe. As revealed by R vs T curves, and the superconductive transition is observed to be characterised by two regions: i) a first smooth and wide transition reflecting the continuous reduction in the width of the Nb triangular pads that progressively experience superconductive transition, and ii) a more abrupt transition reflecting the transition of the Nb nanostripe. This work could pave the way concerning the realisation of Nb nanostructures with tunable critical temperature, transition width, and slope.