Influence of surface structure modifications on the growth of carbon-nanotubes on the SiC(0001) surfaces

We report experimental results of carbon nanotubes (CNTs) formation on SiC(0001) surfaces by scanning tunneling microscopy (STM) and transmission electron microscopy ITEM). The CNTs were formed densely and uniformly after annealing a SiC(0001) surface at 1700 degrees C in a low vacuum. However, the CNTs were not formed after annealing the SiC(0001) surface at 1050 degrees C in an ultra-high vacuum followed by annealing the surface at 1700 degrees C in the low vacuum. From the STM and TEM observations, we found that the graphite layers without defects obstruct the formation of the precursor of CNTs on the SiC(0001) surface. (c) 2006 Elsevier B.V. All rights reserved.