The birth of carbon nanotubes is an important result after the discovery of C60 which is a new structure of carbon atoms arranged in a rolled carbon sheet with various chiralities which is so different from other nanostructured materials. Multi-wall carbon nanotubes were discovered in 1991 and later single wall carbon nanotubes with a diameter of ~1nm in 1993. Carbon nanotubes exhibit therefore so unique properties of electricity, mechanical strength, and thermal conductivity that make them so useful in composite materials, scanning probes, flat panel displays, electrodic materials, catalyst supports, hydrogen storage, gas sensors, and other high tech materials. Carbon nanotubes have been successfully fabricated by arc discharge, chemical vapor deposition, laser evaporation, plasma enhanced chemical vapor deposition, etc. For a wide variety of carbon nanotubes, metal catalysts are often required which is particularly true for the single wall carbon nanotubes. From the basic sciences to the industrial applications carbon nanotubes are consistently the most important issue in nanotechnology which has been constantly emphasized throughout the scientific world, thus leading to significant progresses and major breakthroughs in research and development in recent years.
