Structure-controlled synthesis of single-walled carbon nanotubes with nonmagnetic- catalyzed plasma CVD and their electronic Properties

This work covers the analysis of the nonmagnetic-catalyzed plasma chemical vapor deposition (pcvd) of singlewalled carbon nanotubes (swnts). the selective growth of swnts by the nonmagnetic catalyst using pcvd is realized for the first time. experimental investigations are presented, which allow to get a comprehensive picture of the nonmagnetic catalytic growth of swnts by pcvd. the pcvd growth of swnts is performed on an alumina supported au catalyst using methane as a carbon source. the methodologies to accomplish the controlled growth of swnts, i.e., diameter, density, and chirality are investigated. the au catalyst can afford the swnts growth with narrow diameter and chirality distribution with pcvd by carefully adjusting the experimental parameters. methane pcvd on the au catalyst under well defined conditions produced predominantly (6,5) swnts according to raman, uv-vis-nir absorption, and photoluminescence excitation/emission (ple) spectroscopic characterizations. the high yield of (6,5) semiconducting swnts produced by the structure controlled synthesis described above is promoted us to directly use the as-synthesized swnts for constructing nanotube field effect transistors (fets), which suggests the swnts grown from the nonmagnetic catalyst with pcvd display the best device performance in comparison with thermal chemical vapor deposition (tcvd) synthesized and magnetic catalyzed swnts based devices. based on the magnetic measurements with the au catalyzed swnts, we observe that the nonmagnetic catalyzed swnts show ferromagnetic features, which suggest that the ferromagnetic features might come from the swnts itself. hence this narrow-chirality distributed au catalyzed swnts selectively grown with pcvd could be attractive to both fundamental studies of intrinsic magnetic properties of swnts and industrial applications to nanoelectronics.