Characteristics of Nitrogen-doped Carbon Nanotubes Synthesized by Using PECVD and Thermal CVD

Nitrogen-doped carbon nanotubes (N-CNTs) are synthesizd by using plasma-enhanced chemical vapor deposition (PECVD) and thermal chemical vapor deposition (TCVD) because PECVD and TCVD are attractive methods for producing N-CNTs. In this paper, we report the experimental observation of nitrogen incorporation in multiwalled carbon nanotubes grown by using these methods. XPS analysis indicates a shift and broadening of the C 1s spectra peak with increasing disorder induced by nitrogen doping. The N 1s XPS spectra of N-CNTs grown by using PECVD show various structures such as graphitic, pyridinic and N-gaseous forms, while N-CNTs grown by using TCVD have only a graphitic form. Each structure affects the electronic properties of N-CNTs in a different way. TCVD provides a more profitable synthesis method for n-type CNTs while PECVD supports the synthesis of activated N-CNTs with no post-treatment.