Metastable and Nanostructured Materials

The internal CNT – metal interface: FePt, FeNi

Carbon nanotubes (CNT) are prepared by thermal as well as plasma-enhanced chemical vapour deposition from metal catalyst nanoparticles (e.g. FeNi, FePt). The growth of the CNT is commonly understood in the way that a carbon containing gas is decomposed at the catalyst surface. The carbon atoms then diffuse through the catalyst particles and get released at the particle substrate interface. The so created internal interface between the catalyst particle and the CNT is of interest in terms of better understanding the mechanisms that are governing the growth of the CNT. For instance, for FePt terminated CNT the (111) facet is energetically favoured for the release of carbon so that graphene layers are emerging predominantly from this facet.

Further reading: D. Pohl et al., Phys. Rev. Lett. 107, 185501 (2011) URL

Close-ups of the internal metal-carbon interface in FePt-terminated CNTs. a) Tip-region of a FePt-terminated CNT. The [001] easy axis of magnetisation and the [110] zone axis orientation are indicated by an arrow and an encircled cross, respectively. The insert shows the Fourier transform of the particle section. Super structure reflections indicating the ordered L10 phase and the (regular) [111] reflection are labelled with yellow and green symbols, respectively. b) Magnification of the marked region in fig. a showing the graphene layers emerging from the (111) facets of the catalyst particle. c) Atomic growth model. The concentric graphene sheets emanate mainly from the Pt-rich {111} catalyst particle facets.




Dr. Darius Pohl
Phone: +49-351-4659-758