Synthesis of Single-Walled Carbon Nanotubes for Enhancement of Horizontal-Alignment and Density

We present a synthesis of single-walled carbon nanotubes(SWNTs) for enhancement of parallel-alignment and density using chemical vapor deposition with methane feed gas. As-purchased ST-cut quartz substrates were heat-treated and line-patterned by electron-beam lithography in order to grow SWNTs with parallel alignment. We investigated the effects of various synthesis parameters such as catalyst oxidation, reduction, and synthesis conditions in order to enhance both tube density and degree of parallel alignment. The condition of 1 Å of Fe catalyst film, atmospheric oxidation at 750ºC for 10 min, reduction under 400 Torr for 5 min, and growth at 865ºC under 300 Torr yields 33 tubes/10µm, which is the highest tube density with parallel alignment. Based on the results of atomic force microscope and Raman spectroscopy, it was found that SWNTs have diameter range of 0.8-2.0 nm. We believe that the present work would contribute to the developmen