Selective Growth of Metal-Free Metallic and Semiconducting Single-Wall Carbon Nanotubes

A major obstacle for the use of single-wall carbon nanotubes (SWCNTs) in electronic devices is their mixture of different types of electrical conductivity that strongly depends on their helical structure. The existence of metal impurities as a residue of a metallic growth catalyst may also lower the performance of SWCNT-based devices. Here, it is shown that by using silicon oxide (SiO_x) nanoparticles as a catalyst, metal-free semiconducting and metallic SWCNTs can be selectively synthesized by the chemical vapor deposition of ethanol. It is found that control over the nanoparticle size and the content of oxygen in the SiO_x catalyst plays a key role in the selective growth of SWCNTs. Furthermore, by using the as-grown semiconducting and metallic SWCNTs as the channel material and source/drain electrodes, respectively, all-SWCNT thin-film transistors are fabricated to demonstrate the remarkable potential of these SWCNTs for electronic devices.

Semiconducting and metallic single-wall carbon nanotubes (SWCNTs) are controllably synthesized using silicon oxide nanoparticles with tuned oxygen deficiencies as a catalyst. Totally metal-free, all-SWCNT thin-film transistors are fabricated using the as-grown semiconducting and metallic SWCNTs as channel and source/drain electrodes, respectively, which demonstrates desirable overall performance.

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