Study of field emission of multiwalled C nanotubes from arc discharge
S. Bellucci, C. Balasubramanian, G. Giannini, M. Marchetti, F. Micciulla and M. Regi
INFN-Laboratori Nazionali di Frascati, IT
field emission, carbon nanotubes, chemical vapor deposition, arc discharge
Carbon nanotubes (CNT) were synthesized by DC thermal plasma method. After optimizing the synthesis parameters like the pressure, current etc., the synthesized products especially the anodic deposit was characterized by electron microscopies like Scanning Electron and Transmission Electron microscopies. The morphology of the product was ascertained to be multiwalled carbon nanotubes in large ratio. The diameters of these nanotubes were of the order of 30 – 50 nm and the lengths extending upto a micron and sometimes even 2 or 3 microns.
These nanotubes were then studied for its field emission properties. The CNTs were deposited on a metal stub which acted as the cathode. Care was taken to ensure complete covering of the stub to remove any possibility of emission from the metallic stub itself. The emission studies were performed in a stainless steel chamber under a dynamic vacuum of better than 10 -6 torr. The field emitted current was detected using a phosphor coated ITO (Indium tin oxide) glass. The phosophorous coating also helped in imaging the tips of the nanotubes. This was crucial in estimating accurately the emitting area and thus the field enhancement factor. The I-V curves and F-N plot for the field emission were recorded for various distances between the electrodes. These results will be shown in the presentation, where also the comparison with the electron emission properties of CNTs obtained by CVD will be shown, for comparison.
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Nanotech 2006 Conference Program Abstract