Atomistic to Circuit Level Modeling of Defective Doped SWCNTs with Contacts for On-Chip Interconnect Application

Carbon nanotubes (CNTs) due to their high electrical/thermal conductivity, high ampacity, high tolerance to electro-migration [1] and small dimensions make them an ideal candidate for future on-chip interconnects [2]. Fabricating the CNTs, random chirality and some defects are introduced which can degrade the CNT electrical properties [3]. Additionally, the contact resistance between metal and CNT presents additional parasitics that impose restraints on the electron transport. Electrical models of CNT for interconnect application were developed several years ago [4-5]. In this paper, we explored on doped and defective single-wall CNTs (SWCNT (24,0)) including contact resistance as important physical parameters to assess the performance of fabricated SWCNTs realistically for back-end-of-line (BEOL) on-chip interconnects on VLSI circuit application

Progress on Carbon Nanotube BEOL Interconnects

This article is a review of the current progress and results obtained in the European H2020 CONNECT project. Amongst all the research on carbon nanotube interconnects, those discussed here cover 1) process & growth of carbon nanotube interconnects compatible with back-end-of-line integration, 2) modeling and simulation from atomistic to circuit-level bench-marking and performance prediction, and 3) characterization and electrical measurements. We provide an overview of the current advancements on carbon nanotube interconnects and also regarding the prospects for designing energy efficient integrated circuits. Each selected category is presented in an accessible manner aiming to serve as a review and informative cornerstone on carbon nanotube interconnects

Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise

The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue

The 226Ra–Ba relationship in the North Atlantic during GEOTRACES-GA01

International audienceWe report detailed sections of radium-226 (226 Ra, T 1/2 = 1602 years) activities and barium (Ba) concentrations determined in the North Atlantic (Portugal-Greenland-Canada) in the framework of the international GEO-TRACES program (GA01 section-GEOVIDE project, May-July 2014). Dissolved 226 Ra and Ba are strongly correlated along the section, a pattern that may reflect their similar chemical behavior. Because 226 Ra and Ba have been widely used as tracers of water masses and ocean mixing, we investigated their behavior more thoroughly in this crucial region for thermohaline circulation, taking advantage of the contrasting biogeochemical patterns existing along the GA01 section. We used an optimum multiparameter (OMP) analysis to distinguish the relative importance of physical transport (water mass mixing) from nonconservative processes (sedimentary, river or hydrothermal inputs, uptake by particles and dissolved-particulate dynamics) on the 226 Ra and Ba distributions in the North Atlantic. Results show that the measured 226 Ra and Ba concentrations can be explained by conservative mixing for 58 and 65 % of the samples, respectively , notably at intermediate depth, away from the ocean interfaces. 226 Ra and Ba can thus be considered conservative tracers of water mass transport in the ocean interior on the space scales considered here, namely, on the order of a few thousand kilometers. However, regions in which 226 Ra and Ba displayed nonconservative behavior and in some cases de-coupled behaviors were also identified, mostly at the ocean boundaries (seafloor, continental margins and surface waters). Elevated 226 Ra and Ba concentrations found in deep-water in the West European Basin suggest that lower Northeast Atlantic Deep Water (NEADWl) accumulates 226 Ra and Ba from sediment diffusion and/or particle dissolution during transport. In the upper 1500 m of the West European Basin, deficiencies in 226 Ra and Ba are likely explained by their incorporation in planktonic calcareous and siliceous shells, or in barite (BaSO 4) by substitution or adsorption mechanisms. Finally, because Ba and 226 Ra display different source terms (mostly deep-sea sediments for 226 Ra and rivers for Ba), strong decoupling between 226 Ra and Ba were observed at the land-ocean boundaries. This is especially true in the shallow stations near the coasts of Greenland and Newfoundland where high 226Ra ∕ Ba ratios at depth reflect the diffusion of 226Ra from sediment and low 226Ra ∕ Ba ratios in the upper water column reflect the input of Ba associated with meteoric waters

New insights on the 7Be cycle in the ocean

International audienc

New insights on the 7Be cycle in the ocean

International audienc

New insights on the 7Be cycle in the ocean

International audienc

Radium-228 as a tracer of dissolved trace element inputs from the Peruvian continental margin

International audienceContinental margins play a central role in the composition of seawater by being an important source of trace element essentials to the functioning of the ocean ecosystems. Here, we measured long-lived radium isotopes (Ra-226, Ra-228) along a zonal transect at 12 degrees S (US GEOTRACES GP16) in the eastern tropical South Pacific Ocean. We used Ra-228 to quantify the trace element and isotope (TEI) fluxes (DMn, DFe, and DCo) delivered from the Peruvian continental i) shelf and ii) slope. First, elevated Ra-228 activities were measured in surface water over the entire transect (similar to 8500 km), evidence that the continental shelf is an important source of sediment-derived TEIs not only to coastal areas, but to central Pacific Ocean waters. Modeled Ra-228 shelf fluxes combined with water column dissolved TEI/Ra-228 ratios were used to quantify the shelf-ocean input rates (normalized to shelf-area) for DMn (3.3 x 10(3) mu mol m(-2) y(-1)), DFe (1.5 x 10(3) mu mol m(-2) y(-1)), and DCo (1.0 x 10(2) mu mol m(-2) y(-1)). Second, co-occurring plumes of Ra-228, DFe, and DMn extended over 1800 km from the margin at 1000-2500 m depth, indicative of a continental slope sediment TEI input to the intermediate water column. The Ra-228 gradient allowed us to derive an effective horizontal eddy diffusion coefficient (K-h) of 46 m(2) s(-1), which in turn permitted the calculation of slope sediment DMn (6.4 mu mol m(-2) y(-1)) and DFe (5.9 x 10(2) mu mol m(-2) y(-1)) fluxes based on their offshore concentration gradients. On the scale of the South Pacific continental margin between 0-20 degrees S, the DMn shelf flux is approximately 2-3 orders of magnitude higher than the slope flux, while the DFe shelf/slope flux is similar to 3:1. Both shelf and slope sediment derived DMn was transported over a significant distance towards the ocean interior, while DFe concentration gradients were steep, consistent with longer water column residence time for DMn as compared to DFe in marine systems. These findings highlight the importance of considering the continental slope-ocean boundary in the oceanic budgets of biologically-important trace elements