Growth and properties of carbon nanotubes

[摘要] Carbon buckytubes are widely known to be made on the cathode of a DC arc. The key aspect of the technique is an extremely high electric field (10$sp7$ Vcm$sp{-1}$). Generalizing from this method, we attempted the growth of buckytubes by pyrolysis of hydrocarbons in the high electric field established between an 8 mm commercial carbon fiber, later in the experiment thinner carbon fibers, and an opposing electrode. This research led us to conclude that the continuous growth of buckytubes could only start with a ;;seed crystal;;--a perfect nanotube. We also observed field emission from buckytubes at a low onset voltage (60 Volts) and with a high current density (up to 10$sp6$ A/cm). The onset voltage for emission depends on the history of the nanotube. The field emission from buckytubes after laser annealing versus after micro amp emission shows the difference that could be attributed to two distinct states of the tube tips: closed tips and open tips.

[发布机构] Rice University

[效力级别] Materials science