Horizontally-Aligned Single-Walled Carbon Nanotubes on Sapphire: Growth Mechanism and Characterization

In this paper, the authors reported the recent progress on the growth and characterization of aligned single-walled carbon nanotubes (SWNTs) on sapphire substrate. They introduced the position-and direction-controlled growth of SWNTs on a sapphire substrate and showed the highly-aligned SWNTs grown from the Fe-based wet catalyst patterned with the aid of an electron beam lithography technique. The catalyst patterning was found to give much better alignment than those grown on the homogeneously deposited catalyst. This is because the non-patterned area of the sapphire is kept clean without the catalyst contamination. To monitor the growth period chemical vapor deposition (CVD) is used with the combination of Raman mapping measurements.