Selective growth of carbon nanotubes on Si microfabricated tips and application for electron field emitters

In this article, we present the results on the synthesis and electron emission characteristics of an individual and a carbon nanotube (CNT) bundle on a Si tip. The Si tip with diameter of about 20 nm at the apex and the tip height of 5 mum was fabricated using Si microfabrication process. Individual and carbon nanotubes bundle were selectively grown at the apex of the Si tip using a hot-filament chemical vapor deposition with a mixture of C2H2 and H-2 gases under a negative substrate biasing. Electron field emission characteristics of the Si tips with and without the individual CNT on the same substrate were measured in a vacuum of 1.7 x 10(-4) Pa. Threshold or turn on voltages defined at the emission current of 10 pA of approximately 40 V (4 V/mum) and 200 V (20 V/mum) were found for the Si tips with and without the individual CNT, respectively. Emission current and emission light pattern of the emitted electrons from the carbon nanotubes bundle were also studied. (C) 2003 American Vacuum Society.