The role of Ti interlayer in carbon nanotube growth

Vertically aligned multi-wall carbon nanotubes (CNTs) were grown on Ni/Ti/Si substrate by thermal chemical vapor deposition method in a microwave heating system. The results showed that vertically aligned CNTs could be uniformly grown on a large area substrate of 3 inch diameter. The Ti interlayer couldn't obstruct the interdiffusion of Ni and Si and the inward diffusion of O, Ti and C. The C atoms for CNTs growth were supplied from Ni particles at an early stage and from Ti interlayer at a later stage in the growth process.