A simple and versatile method for statistical analysis of the electrical properties of individual double walled carbon nanotubes

Double-walled carbon nanotubes (DWNTs) are potential candidates for new generation of on chip interconnections due to their nearly metallic behaviour. For such large scale integration purpose it is mandatory to characterize their electrical properties in a statistical way. We thus propose a new methodology for characterizing in one step, the electrical properties of a large population of nanotubes. The method enables to obtain histograms of the conductance and maximum current density of individual nanoobjects

A simple and versatile micro contact printing method for generating carbon nanotubes patterns on various substrates

We present an optimized process for generating at low cost, patterns of carbon nanotubes (CNTs) on a large variety of substrates through a simple micro contact printing method. This method meets the requirements for the integration of CNTs into microdevices, for applications in microelectronics (interconnects), flexible electronics (printed conductive electrodes) and biodevices (biosensors and biosystems for regenerative medicine). We have optimized a new method for inking PolyDiMethylSiloxane (PDMS) stamps with CNTs that turned out to improve significantly the quality of the printed features over large surfaces. This inking step is performed by adapting a spray-coating process leading to a dense and homogeneous coating of the stamp with a thin layer of CNTs. The printing step is performed using a solvent mediation, allowing us to pattern this thin layer of CNTs onto various substrates by contact through a thin film of liquid. We demonstrate that this soft and rapid methodology can lead to the realization of CNTs patterns with versatile geometries onto various substrates at the micron scale. Examples of applications for CNTs interconnects and flexible electronics are rapidly shown

Electrical properties and non-volatile memory effect of the [Fe(HB(pz)3)2] spin crossover complex integrated in a microelectrode device

We report on the deposition of thin films of the [Fe(HB(pz)3)2] (pz = pyrazolyl) molecular spin crossover complex by thermal evaporation. By means of impedance measurements and Raman microspectroscopy, we show that the films maintain the structure and properties of the bulk material. The conductivity of the films decreases by ca. 2 orders of magnitude when the freshly deposited compound goes through a first (irreversible) thermal phase change above ca. 380 K. This property can be exploited as a non-volatile (read-only) memory effect

Microcontact printing process for the patterned growth of individual CNTs

We report an original approach to pattern a substrate with isolated carbon nanotubes. Through the improvement of the microcontact printing technique by the use of a new composite stamp, we were able to produce on flat substrates micrometric features of a catalyst suitable for the localised growth of single-walled carbon nanotubes by catalytic chemical vapour deposition. This catalyst material is for the first time prepared via an original sol–gel process. The growth of straight carbon nanotubes between the patterns was observed and a method to promote the controlled growth of such isolated nanoobjects is thus conceivable

Multi-scale engineering for neuronal cell growth and differentiation

In this paper we investigate the role of micropatterning and molecular coating for cell culture and differentiation of neuronal cells (Neuro2a cell line) on a polydimethylsiloxane substrate. We investigate arrays of micrometric grooves (line and space) capable to guide neurite along their axis. We demonstrate that pattern dimensions play a major role due to the deformation of the cell occasioned by grooves narrower than typical cell dimension. A technological compromise for optimizing cell density, differentiation rate and neurite alignment has been obtained for 20 lm wide grooves which is a dimension comparable with the average cell dimension. This topographical engineered pattern combined with double-wall carbon nanotubes coating enabled us to obtain adherent cell densities in the order of 104 cells/cm2 and a differentiation rate close to 100%

Nanodevices for correlated electrical transport and structural investigation of individual carbon nanotubes

We report a new approach to the correlation of the structural properties and the transport properties of carbon nanotubes. Through an original combination of UV lithography, custom-made photosensitive sol–gel resist and deep reactive ion etching (RIE), we have successfully integrated membrane technology and nanodevice fabrication for the electrical connection of individual carbon nanotubes. After single wall nanotube (SWNT) deposition by molecular combing and contacting using high resolution electron beam lithography, we obtain a device that allows both the investigation of the nanotubes and the contact regions by transmission electron microscopy (TEM) and the measurement of the electronic transport properties of the same individual nano-object. The whole fabrication process is detailed and the demonstration that the micro membranes are suitable for both TEM inspection and nanoelectrode fabrication is given

A combination of capillary and dielectrophoresis-driven assembly methods for wafer scale integration of carbon-nanotube-based nanocarpets

The wafer scale integration of carbon nanotubes (CNT) remains a challenge for electronic and electromechanical applications. We propose a novel CNT integration process relying on the combination of controlled capillary assembly and buried electrode dielectrophoresis (DEP). This process enables us to monitor the precise spatial localization of a high density of CNTs and their alignment in a pre-defined direction. Large arrays of independent and low resistivity (4.4 x 10-5 omega m) interconnections were achieved using this hybrid assembly with double-walled carbon nanotubes (DWNT). Finally, arrays of suspended individual CNT carpets are realized and we demonstrate their potential use as functional devices by monitoring their resonance frequencies (ranging between 1.7 and 10.5 MHz) using a Fabry–Perot interferometer

Interview de Christophe Vieu, directeur de recherche au LAAS, Toulouse, le 8 décembre 2017

Plongé au cœur des nanos, Christophe Vieu souligne la diversité des secteurs touchés par l’approche nano. À l’idée d’une convergence des secteurs scientifiques, il oppose l’image d’une espèce invasive. Il se sent de ce fait investi d’une responsabilité de l’ensemble des technosciences.Actively engaged in research at the very heart of the nanosciences, Christophe Vieu emphasises the wide range of sectors touched by the nano approach. He deploys the image of an invasive species as a counterpoint to that of the convergence of scientific fields. The invasive nature of the domain means that researchers have a responsibility with respect to all the other contemporary technosciences