Adsorption and diffusion of silicon on the exterior surface of carbon nanotubes were crucial for the growth of silicon carbide nanotubes from carbon nanotubes. First-principles calculations were carried out in order to explore these processes. It was found that a silicon atom preferred to be adsorbed at the bridge site above a C-C bond tilted to the tube axis with binding energy of 1.29 to 1.61eV. The adsorbed silicon atoms have high mobility with diffusion energy barriers less than 0.06eV. The energetically favorable diffusion paths were oriented along the tube axis.

Atomic-Scale Characterization of Silicon Diffusion on Carbon Nanotubes. Zhang, H., Zhang, X., Zhao, M., Wang, Z.: Physica E: Low-Dimensional Systems and Nanostructures, 2010, 43[2], 610-3

Figure 3

Diffusion of Si in amorphous C film