Direct Synthesis of Single-Walled Carbon Nanotubes on Silicon and Quartz-Based Systems

Abstract

A newly developed technique of synthesizing single-walled carbon nanotubes (SWNTs) directly on the surface of Si and quartz substrates is introduced in this report. This technique adopted a liquid-based dip-coating method to mount a very small amount of catalyst metals on the surface of substrates using Mo/Co bimetallic acetate solution. The merits of this approach lie in its easy, costless, and geometry-flexible nature compared with conventional sputtering and deposition approaches. We used the alcohol catalytic chemical vapor deposition (ACCVD) method that can produce relatively high-quality SWNTs even at low temperatures down to 600°C. This low-temperature process contributes to the prevention of the agglomeration of catalytic metals on the surface and chemical reaction between catalytic metal and silicon, which helps us to eliminate any kind of intermediating support materials. Thereby synthesized SWNTs on Si and quartz substrates under various CVD conditions are characterized by means of SEM, TEM, Raman scattering, and optical absorbance measurements. The underlying reasons our experimental procedure and choice of catalyst worked for the synthesis of SWNTs are discussed through comparative studies. At the end of this report, some possible applications of this technique are stated.