The characterization of boron-doped carbon nanotube arrays

In this study, we directly synthesized boron-doped carbon nanotubes (CNTs) by using trimethylborate (B(OCH3)(3)) as doping sources in a microwave plasma chemical vapor deposition system (MPCVD). Doping boron causes the growth rate of CNTs to decrease. This might be due to the high oxygen content contained in the doping source that induces oxidation of graphite. The bamboo-like nanostructure of the carbon tubes disappeared with boron doping. Raman spectrum shows the higher I-D/I-G ratio in boron-doped CNTs. This implies the decrease of graphitization in boron-doped CNTs. In addition, doping boron could enhance the field emission property by increasing the current density by more than 30% (from 350 to 470 mA/cm(2) at 2.2 V/mum). (C) 2003 Elsevier Science B.V. All rights reserved.