Controlling growth of aligned carbon nanotubes from porous silicon templates

Fabricating well-aligned carbon nanotubes, especially, on a silicon substra te is very important for their applications. In this paper, an aligned carb on nanotube array has been prepared by pyrolysis of hydrocarbons catalyzed by nickel nanoparticles embedded in porous silicon (PS) templates. High-mag nification transmission electron microscopy images confirm that the nanotub es are well graphitized. The PS substrates with pore sizes between 10 and 1 00 nm play a control role on the growth of carbon nanotubes and the diamete rs of the tubes increase with the enlargement of the pores of the substrate s. However, such a control role cannot be found in the macro-PS substrates.