Multi-scale modeling of chemical vapor deposition processes for thin film technology

High Knudsen number fluid flow at near-standard temperature and pressure conditions using precision nanochannels

“…The viscous drag reduction associated with high Kn flows have implications for more efficient filtration of industrial gases (Pabby et al 2008), design of high altitude aerospace vehicles (Bird 1978(Bird , 2003, medical oxygenation equipment (Chapman et al 2008, and thin film deposition systems (Kleijn et al 2007). In addition to providing a rare demonstration of high-Kn flow characteristics at high (near-atomspheric) pressure, the engineered nanochannels provide a platform for the research community to directly investigate nanoscale fluid dynamics, which has previously been confined largely to theoretical and computational methods.…”

Carbon nanotube reactor: Ferrocene decomposition, iron particle growth, nanotube aggregation and scale-up

“…Common use for individual SWCNTs is as building blocks for electronics applications as a result of their unique electrical properties, whereas aggregates of SWCNT and double-walled carbon nanotubes (DWCNT) can be used as high performance nanotube fibres due to their exceptional mechanical properties (Motta et al, 2007a;Koziol et al, 2007). One of the most promising methods of mass production of carbon nanotubes to date is chemical vapour deposition (see Kleijn et al, 2007;Jensen et al, 1991 for a review on the flow and transport in a chemical vapour deposition reactor) in which the cracking of a carbon source at the surface of floating nanoparticles of a transition metal leads to the growth of the nanotubes (Joselevich et al, 2008).…”

Comparison of Coupling Methods for Linking Between Reactor and Feature Scales

“…The reactor scale supplies the feature scale with information on the gases entering the feature scale, while the feature scale supplies information on the surface reaction rate to the reactor scale. A recent literature survey on multi-scale modeling of CVD by Kleijn et al [5] cites two different approaches currently being used to bi-directionally link macroscopic reactor and microscopic feature scales. The first of these approaches, proposed by Gobbert et al, [6] couples the feature and reactor scales through the net flux into the surface.…”

“…The second approach, mentioned by C.R. Kleijn et al, [5] was proposed by Rodgers and Jensen, [7] and used effective reactivity maps to link the reactor and feature scales. These effective reactivity maps were generated based on the net flux across a source plane offset from the surface.…”