High-precision selective deposition of catalyst for facile localized growth of single-walled carbon nanotubes

In the liquid-based dip-coating, the hydrophilicity of a Si/SiO(2) substrate is found to be critical for the successful deposition of catalyst and hence the growth of single-walled carbon nanotubes (SWNTs). When the surface is functionalized by a self-assembled monolayer (SAM) and becomes hydrophobic, no catalyst remains and no SWNT grows. This concept can be utilized to localize the growth of SWNTs at designated regions where SAMs were selectively removed by, e.g., UV or electron beam. Patterned high-quality as-grown SWNTs with a potential line width of approximately 10 nm can be obtained.