Carbon nanotube catalysis by metal silicide: resolving inhibition versus growth

The catalytic activity of metal silicide for carbon nanotube (CNT) nucleation and growth is reported by systematically evaluating CNT synthesis on different metal silicide phases compared with pure metal catalysts. Using a combination of high-resolution microscopy, x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS), the influence of various pretreatment annealings on 1, 5 and 10 nm Ni and Co films sputter deposited on pristine Si(100) and SiO2 substrates has been explored in relation to their ability to catalyse CNT growth under a broad range of synthesis conditions. Under certain pretreatment and growth conditions metal silicide nanoparticles are as catalytically active as pure metal nanoparticles. The impact of these findings is significant. The considerable expertise on metal silicide already existing in silicon technology can be applied and extended for the integration of CNTs in electronics.