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

A novel route to regularly arrange Fe nanoparticles in three-dimensions ove r large areas, just like a crystalline cubic lattice of atoms, is reported. The cylindrical Fe particles, acting as the catalyst for carbon nanotube f ormation by conventional chemical vapor deposition method, are located in t he nanotube cavities. The inner nanotube cavities protect and support the F e particles, which are periodically spaced in the aligned nanotubes. The in terparticle 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.