Selective synthesis of zigzag-type aligned carbon nanotubes on SiC (000-1) wafers

Zigzag-type carbon nanotubes have been selectively produced by surface decomposition of a well-polished SiC single crystal. The SiC wafer was heated to 1500 degreesC at a very small heating rate under vacuum. Transmission electron microscopy (TEM) and electron diffraction patterns revealed that almost all the well-aligned carbon nanotubes formed perpendicular to the SiC (0 0 0 -1) surface were double-walled and of zigzag type. The results of high-resolution electron microscopy (HREM) indicate that the zigzag type structure evolves from the Si-C hexagonal networks in the SiC crystal by the collapse of carbon layers remaining after the process of decomposition. (C) 2002 Elsevier Science B.V. All rights reserved.