Growth mechanism of iron-filled carbon nanotubules

Iron-filled nanotubules were synthesized in a carbon are in the presence of He and Fe(CO)(5) gases. The consumption of the Fe(CO)(5) inside the are chamber was controlled by the pressure of the pentacarbonyliron Fe(CO)(5) gas. Different shapes and filling extents of nanotubules were found depending on the pentacarbonyliron concentration supplied. Based on high-resolution transmission electron microscope images, we propose a growth model of iron-filled carbon nanotubules. The growth proceeds through the deposition and surface diffusion of carbon on the liquidlike metal. The hollow tubules probably grow spontaneously. (C) 1996 American Institute of Physics.