Chirality specific and spatially uniform synthesis of single-walled carbon nanotubes from a sputtered Co-W bimetallic catalystElectronic supplementary information (ESI) available: Raman spectroscopy (G-band) of SWNTs grown from Co and Co-W catalyst; Kataura plot for chirality assignment; Raman spectra (RBM region) of SWNTs grown from low temperature reduced monometallic Co; relative intensities of the 197 cm−1 peak with respect to the total sum intensity; TEM image of Co-W catalyst reduced at si

Synthesis of single-walled carbon nanotubes (SWNTs) with well-defined atomic arrangements has been widely recognized in the past few decades as the biggest challenge in the SWNT community, and has become a bottleneck for the application of SWNTs in nano-electronics. Here, we report a selective synthesis of (12, 6) SWNTs with an enrichment of 50%-70% by chemical vapor deposition (CVD) using sputtered Co-W as a catalyst. This is achieved under much milder reduction and growth conditions than those in the previous report using transition-metal molecule clusters as catalyst precursors ( Nature , 2014, 510 , 522). Meanwhile, in-plane transmission electron microscopy unambiguously identified an intermediate structure of Co 6 W 6 C, which is strongly associated with selective growth. However, most of the W atoms disappear after a 5 min CVD growth, which implies that anchoring W may be important in this puzzling Co-W system. Chirality specific and spatially uniform single-walled carbon nanotubes are synthesized by sputtered Co-W catalyst. An intermediate structure of catalyst is identified.