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

Abstract

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 100 o C. The temperature at the catalyst can easily be as high as 1000 o C 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.PACS: 61.46.Fg Nanotubes.

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

“…This change is permanent since we observe that the temperature remains constant when the ethylene gas is turned off again. As we have shown previously [9,12], the temperature gradient close to the heater is very high, on the order of 100 o C /µm which means that the nanotube growth is restricted to the highly localised hot zone on the heater. Growth is performed for the desired time, at the end of which the chamber is evacuated and the current is abruptly turned down to 10 mA, thus reducing the electrode temperature to well below the growth temperature window but still allowing growth to be efficiently restarted when the temperature is increased again.…”

“…This allows us to grow nanotubes directly on contact electrodes. An additional advantage is that we can also easily switch between multi-walled and single-walled nanotubes by adjusting the growth conditions [9,12].…”

Growth of Aligned MWNT Arrays Using a Micrometer Scale Local-Heater at Low Ambient Temperature

“…Simulations of the heater temperature, illustrating this effect have been published previously. 12 However this small gradient is responsible for the formation of an additional level of tube organisation inside the arrays. The outer regions of the arrays are straighter and the effective length of each tube at the array edge is shorter than that of inner "wavy" tubes.…”

Use of Carbon nanotubes in potential electronics packaging applications

“…However the actual heating effect from the plasma in some works is questionable [96] and there is proof that the CNTs grown at lower temperature have poorer structures than those grown at higher temperature [97]. An alternative strategy is to locally heat the growth sites instead of the whole growth substrate [98,99]. This method however adds the complexity of fabricating micro heaters and electrical connection during the growth.…”