Effect of Co catalyst on PECVD growth of carbon nanotubes for NEMS applications

In this paper the effect of cobalt (Co) catalyst on the growth of carbon nanotubes (CNTs) was studied. CNTs were vertically grown by plasma enhanced chemical vapor deposition method (PECVD) at 700°C with various sputtered Co catalyst thicknesses. Experimental results shows that for carbon nanotube growth duration of 20 minutes, growth was only achieved with thinner catalyst layers but when the growth duration was doubled, high density of CNTS were also observed with thicker catalyst layers with taller nanotubes formed. The nucleation of the catalyst with various thicknesses was also studied as the absorption of the carbon feedstock is dependent on the initial size of the catalyst island

Field ionization using densely spaced arrays of nickel-tipped carbon nanotubes

A field ionization source based on densely spaced, vertically aligned carbon nanotubes (CNTs) has been developed and evaluated. The CNTs contained nickel particles at their tips. This source would be suitable for analytical mass spectrometry. With a positive voltage on the dense CNT arrays, the strong electric field generated around the CNT tips has effected field ionization. The ionization of inert gases, including helium, and organic compounds, including acetone and methane, and the control and the transfer of the resulting ions have been achieved. These results represent a base for application of this new ion source in mass spectrometry