Effects of Surface Oxides of SiC on Carbon Nanotube Formation by Surface Decomposition

Abstract

We present consistent theoretical studies of optically heterodyned polarization interferometry (OHPI) with noncollinear arbitrary polarized interacting beams in the framework of the cubic nonlinear optical susceptiblity formalism. Our theoretical treatment is based on the covariant tensorial approach introduced by F I Fedorov. We were able to derive the analytical expressions for the detected OHPI signal. Different methods for measuring the nonlinear susceptibility are also suggested.

Observations of Graphitized SiC Surfaces by STM

“…The plan view of the protrusion is round with a diameter of about 1 nm. It is reported that carbon nanotubes grow not only on (0001) surfaces but also on (0001) surfaces, when the native oxide is removed enough by HF treatment [10]. As the specimens used in this experiment are also treated by HF, it seems that the protrusions are the ends of carbon nanotubes in the initial stage growing on (0001) surfaces.…”

“…6(e) and (f), string-shaped structures are transitionally generated on the C-terminated surface in the annealing process. As carbon nanotubes grow preferably on C-terminated surfaces than Si-terminated surfaces [9,10], the generation of string-shaped structures is considered to be restricted by the growth of carbon nanotubes. Considering the fact that string-shape structures are also generated on the C-terminated surface where step edges are not observed clearly after annealed up to 1000…”

“…It is known that carbon nanotubes, a new material for mechanical and electronic applications, are produced on 6H-SiC(0001) C-terminated surfaces in the direction perpendicular to the surfaces [9]. It has also been found that, on 6H-SiC(0001) Siterminated surfaces, graphite layers or carbon nanotubes with shorter length than that on the C-terminated surfaces are produced depending on sample preparation procedures [10]. Previously, we have found that string-shaped structures consisting of graphite structure are produced along step edges on 6H-SiC(0001) Si-terminated surfaces by annealing in UHV [3].…”

Controlled growth of metal-free vertically aligned CNT arrays on SiC surfaces

“…In this process, not only highly pure but also vertically aligned CNT arrays were grown on the SiC surfaces. Following the first report, many research efforts have been made to understand the growth mechanism and to control the CNT growth in a well-defined way [13][14][15]. Up to now, it has been only shown that atmosphere is critical to the non-catalytic growth of CNTs on SiC.…”

Growth of Graphene-Like Structures on an Oxidized SiC Surface

“…The ends of the CNTs are closed, which indicates that the caps were formed by a lift-up of part of the graphene along the ½111 direction on SiC though the generation of pentagons and heptagons. Nagano et al 8,9 reported that CNTs can grow on both the Si-face and the C-face of SiC in a vacuum of approximately 10 À4 Torr. The growth rate of CNTs on the Si-face of SiC is about 65% of that on the C-face at 1700°C.…”