Growth of vertically aligned single-walled carbon nanotube films on quartz substrates and their optical anisotropy

Films of vertically aligned single-walled carbon nanotubes (SWNTs) with a few micrometer thickness were grown by catalytic chemical vapor deposition (CVD) on quartz substrates. Low-temperature CVD from ethanol was performed by using densely mono-dispersed Co–Mo catalyst of ≈1.0–2.0 nm prepared on quartz substrates by a dip-coating method. Continuous reduction of catalysts with Ar/H2 (3% H2) during CVD was essential for generating dense enough SWNTs with vertical alignment. Vertical alignment was clearly demonstrated by anisotropic optical absorption and transmission characteristics in addition to observations by FE-SEM, TEM and resonance Raman scattering.