Local heating method for growth of aligned carbon nanotubes at low ambient temperature

We use a highly localised resistive heating technique to grow vertically aligned multiwalled nanotube films and aligned single-walled nanotubes on substrates with an average temperature of less than 100oC. The temperature at the catalyst can easily be as high as 1000 oC but an extremely high temperature gradient ensures that the surrounding chip is held at much lower temperatures, even as close as 1μm away from the local heater. We demonstrate the influence of temperature on the height of multi-walled nanotube films, illustrate the feasibility of sequential growth of single-walled nanotubes by switching between local heaters and also show that nanotubes can be grown over temperature sensitive materials such as resist polymer

In situ Raman studies of single-walled carbon nanotubes grown by local catalyst heating

Using in situ Raman spectroscopy we investigate single wall carbon nanotube growth on Mo electrodes,using a highly localized resistive heating technique. Small diameter semiconducting single wall nanotubesgrow very rapidly when the catalyst support is heated to a temperature of 800 C. The G/D ratioshows an interesting time-dependent behaviour. It first decreases, indicating the presence of amorphouscarbon and then significantly increases again after ca. 5 min growth while retaining the position andshape expected for predominantly semiconducting carbon nanotubes

Determination of the Bending Rigidity of Graphene via Electrostatic Actuation of Buckled Membranes

The small mass and atomic-scale thickness of graphene membranes make them highly suitable for nanoelectromechanical devices such as e.g. mass sensors, high frequency resonators or memory elements. Although only atomically thick, many of the mechanical properties of graphene membranes can be described by classical continuum mechanics. An important parameter for predicting the performance and linearity of graphene nanoelectromechanical devices as well as for describing ripple formation and other properties such as electron scattering mechanisms, is the bending rigidity, {\kappa}. In spite of the importance of this parameter it has so far only been estimated indirectly for monolayer graphene from the phonon spectrum of graphite, estimated from AFM measurements or predicted from ab initio calculations or bond-order potential models. Here, we employ a new approach to the experimental determination of {\kappa} by exploiting the snap-through instability in pre-buckled graphene membranes. We demonstrate the reproducible fabrication of convex buckled graphene membranes by controlling the thermal stress during the fabrication procedure and show the abrupt switching from convex to concave geometry that occurs when electrostatic pressure is applied via an underlying gate electrode. The bending rigidity of bilayer graphene membranes under ambient conditions was determined to be $35.5^{+20}_{-15}$ eV. Monolayers have significantly lower {\kappa} than bilayers

Low ambient temperature CVD growth of carbon nanotubes

We show that good quality single-walled and multi-walled carbon nanotubes can be grown on CMOS-compatible metal electrodes at ambient room temperature using highly localised catalyst heating at nanostructured electrodes. The method is relatively straightforward and allows considerable flexibility in the kinds of devices that can be fabricated as well as allowing CVD nanotube growth to take place in the close vicinity of temperature-sensitive materials and devices

Field emission induced deformations in SiO2 during CVD growth of carbon nanotubes

The application of an electric field while growing carbon nanotubes with CVD can induce deformations in the SiO2 substrate. The effect is attributed to field emission from the tubes and Marangoni convection in a small molten SiO2 region underneath the tubes. Postgrowth deformation has been performed as well as large scale deformations using the collective effect of many field emitters. The porosity of one type of deformation is also examined and discussed