Showing papers by "Michael Stadermann published in 2009"
TL;DR: A quantitative model is presented that shows how accumulation of the amorphous carbon patches at the catalyst particle surface and the carbon diffusion to the growing nanotube perimeter causes this abrupt growth cessation and the nonlinear behavior of the growth rate as a function of total process pressure.
Abstract: We have investigated growth kinetics of multiwall carbon nanotube (MWCNT) arrays produced by catalytic thermal decomposition of ethylene gas in hydrogen, water, and argon mixture. The MWCNT growth rate exhibits a nonmonotonic dependence on total pressure and reaches a maximum at ∼750 Torr of total pressure. Water concentrations in excess of 3000 ppm lead to the decrease in the observed growth rate. Optimal pressure and water concentration combination results in a reliable growth of well-aligned MWCNT arrays at a maximum growth rate of ∼30 μm/min. These MWCNT arrays can reach heights of up to 1 mm with typical standard deviations for the array height of less than 8% over a large number of process runs spread over the time of 8 months. Nanotube growth rate in this optimal growth region remains essentially constant until growth reaches an abrupt and irreversible termination. We present a quantitative model that shows how accumulation of the amorphous carbon patches at the catalyst particle surface and the ca...
110 citations
TL;DR: A new growth recipe for producing carbon nanotubes (CNTs) combined with a new bonding technique was implemented in a microfabricated gas chromatography (micro-GC) chip, resulting in better separation efficiency and peak symmetry in the separation of a mixture of five n-alkanes.
84 citations
Patent•
10 Feb 2009TL;DR: In this article, the authors describe a sensor consisting of a gate electrode, a source electrode, and a drain electrode, operatively connected to the gate, the source, and the drain electrodes, with a lipid bilayer around the nanotube or nanowire.
Abstract: A sensor apparatus comprising a nanotube or nanowire, a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer. Also a biosensor apparatus comprising a gate electrode; a source electrode; a drain electrode; a nanotube or nanowire operatively connected to the gate electrode, the source electrode, and the drain electrode; a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer.
27 citations