The formation and characterization of palladium nanowires in growing carbon nanotubes using microwave plasma-enhanced chemical vapor deposition

Multi-wall carbon nanotubes were synthesized on electroplated palladium nanoclusters using a microwave plasma-enhanced chemical vapor deposition system in a mixture of methane and hydrogen as precursors. During the synthesis, Pd was melted to fill up the growing multi-wall carbon nanotubes. A growth mechanism was proposed to describe the Pd filling phenomenon. The multi-wall carbon nanotubes could be burned in oxygen plasma and the filled Pd nanowires could thus be collected. The surface morphology of electroplated Pd clusters and the nanostructure of multi-wall carbon nanotubes with filled Pd nanowires were examined by scanning electron microscopy and transmission electron microscopy, respectively. Raman spectra were used to study the first- and second-order signals of multi-wall carbon nanotubes. Bamboo-shaped carbon nanotubes free of filled Pd were observed under a pure methane atmosphere. (C) 2002 Elsevier Science B.V. All rights reserved.