Macroscopic three-dimensional arrays of Fe nanoparticles supported in aligned carbon nanotubes

A novel route to regularly arrange Fe nanoparticles in three-dimensions over large areas, just like a crystalline cubic lattice of atoms, is reported. The cylindrical Fe particles, acting as the catalyst for carbon nanotube formation by conventional chemical vapor deposition method, are located in the nanotube cavities. The inner nanotube cavities protect and support the Fe particles, which are periodically spaced in the aligned nanotubes. The interparticle spacings can be well-controlled simply by adjusting the feeding interval of ferrocene during the nanotube growth process. Carbon nanotubes, which can carry foreign particles because of capillarity, show potential use in manipulating nanoparticles that otherwise have a strong tendency to aggregate and merge.