Growth of carbon nanotubes on transition metal alloys by microwave-enhanced hot-filament deposition

Carbon nanotubes (CNTs) are successfully grown on alloy substrates made of copper and iron groups by hot-filament chemical vapor deposition method with self-bias induced by a radio-frequency-field. A precursor of the hydrogen etching of alloys to produce catalyst nanoparticles on the substrate surface is crucial to CNT growth. Successful CNT growth on bulk-catalyst alloy substrates such as Cu-Ni, Cu-Fe, Cu-Co, and Cu-Ni-Fe-Co illustrates a new base-growth mechanism, which is unlike the tip-growth mechanism in that eutectic nanoparticles dissolve carbons and then precipitate graphite near the contact surface between the particle and the substrate.