Single-wall carbon nanotubes (SWCNTs) can be either semiconducting or metallic, depending on their chiralities. Semiconducting SWCNTs (s-SWCNTs) are potential channel material of high-performance field effect transistors with advantages of high carrier mobility and excellent flexibility. Usually, as-prepared SWCNTs are a mixture of semiconducting and metallic tubes. Therefore, it is highly important to prepare pure s-SWCNTs to achieve their use in electronics. In this presentation, we report the direct growth of high-quality s-SWCNTs by a floating catalyst chemical vapor deposition (FCCVD) method and by novel catalyst design. We introduce suitable amount of oxygen or hydrogen as etchant during the growth of SWCNTs by the FCCVD method. As a result, metallic SWCNTs with relatively higher chemical reactivity are selectively removed, and s-SWCNTs with a concentration higher than 90% are obtained in large scale [1-2]. On the other hand, we design and prepared novel partially carbon-coated Co catalyst with superior stability compared to traditional transition metals, and obtained s-SWCNT with a narrow band gap distribution [3].
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