Unidirectional and bi-directional growth of carbon nanotubes on the catalytic Co–Zr–N-(O) material

In this paper we have demonstrated the possibility of the MWCNT growth on initially amorphous Co–Zr–N–O alloy thin film which was crystallized during heating followed by formation of Co particles on the surface. It was found that during CVD not only the growth of usual MWCNT array but also the formation of MWCNT arrays with a top covering layer and bilevel MWCNT arrays take place. The details of MWCNT array growth process are discussed. We have found that carbon nanotubes growth strongly depends on the Co concentration in the alloy film. The presented technique of MWCNT growth can be used in the preparation of new advanced engineering materials.