Search

Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties; (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes (this route being particularly relevant for gas- and bio-sensors, opto-electronic devices and energy sources); and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we review our recent results concerning nanotube chemistry and assembly and their use to develop electronic devices. In particular, we present carbon nanotube field effect transistors and their chemical optimization, high frequency nanotube transistors, nanotube-based opto-electronic devices with memory capabilities and nanotube-based nano-electromechanical systems (NEMS). The impact of chemical functionalization on the electronic properties of CNTs is analyzed on the basis of theoretical calculations. To cite this article: V. Derycke et al., C. R. Physique 10 (2009).

In this contribution, we present a numerical study of quantum transport in carbon nanotubes based materials. After a brief presentation of the computational approach used to investigate the transport coefficient (Kubo method), the scaling properties of quantum conductance in ballistic regime as well as in the diffusive regimes are illustrated. The impact of elastic (impurities) and dynamical disorders (phonon vibrations) are analyzed separately, with the extraction of main transport length scales (mean free path and localization length), as well as the temperature dependence of the nanotube resistance. The results are found in very good agreement with both analytical results and experimental data, demonstrating the predictability efficiency of our computational strategy. To cite this article: H. Ishii et al., C. R. Physique 10 (2009).

In recent years, the understanding and accurate simulation of carbon nanotube-based devices has become verychallenging. Conventional simulation tools of microelectronics are necessary to envision the performances and useof nanotube transistors and circuits, but the models need to be refined to properly describe the full complexityof such novel type of devices at the nanoscale. Indeed many issues such as contact resistance, low dimensionalelectrostatics and screening effects, as well as nanotube doping or functionalization, demand for more accuratequantum approaches. In this article, we review our recent progress on multiscale simulations which aim at bridgingfirst principles calculations with compact modelling, including the comparison between semi-classical Monte Carloand quantum transport approaches.R´esum´eSimulation Multi-Echelle des Dispositifs `a Nanotube de CarboneCes derni`eres ann´ees, la compr´ehension et la simulation pr´ecise des dispositifs `a base de nanotubes de car-bone est devenue une tˆache ambitieuse. Les outils de simulation conventionnels de la micro´electronique sontn´ecessaires pour imaginer les performances et l’utilisation des transistors et des circuits `a base de nanotubes,mais les mod`eles doivent ˆetre affin´es pour d´ecrire correctement la complexit´e de ces nouveaux types de dispositifs`a l’´echelle nanom´etrique. En effet, de nombreuses questions comme la r´esistance de contact, l’´electrostatique enbasse dimensionalit´e et les effets d’´ecrantage, et le dopage ou la fonctionnalisation des nanotubes, n´ecessitentdes approches quantiques plus pr´ecises. Dans cet article, nous exposons nos progr`es r´ecents pour des simulationsmulti-´echelles qui visent `a connecter des calculs bas´es sur les premiers principes `a la mod´elisation compacte, enpassant par la comparaison entre les approches Monte Carlo semi-classique et de transport quantique.