Controlled synthesis of aligned carbon nanotube arrays on catalyst patterned silicon substrates by plasma-enhanced chemical vapor deposition

Aligned carbon nanotube (CNT) array has been successfully synthesized from acetylene and hydrogen mixture by radio frequency (rf) plasma-enhanced chem ical vapor deposition (PE-CVD) on patterned iron or cobalt coated silicon s ubstrates. The length of the nanotubes and thus the height of the CNT array s could be controlled by varying the growth time; the width of C the lines was controlled by the size of the openings in the shallow mask. Adjusting t he thickness of the catalyst layer changes the aligned CNT density within t he array. Using, the substrates with a 10-30 nm catalyst layer, the synthes ized CNTs were densely packed and perpendicularly aligned. However, a thick er (more than 60 nm) or a thinner (less than 5 nm) catalyst layer resulted in a significantly reduced CNT density within the array. (C) 2001 Elsevier Science B.V. All rights reserved.