title: Synthesis and thermoelectric power of nitrogen-doped carbon nanotubes.
abstract: We have previously shown that high-purity multiwalled carbon nanotubes (pristine MWNTs) can be prepared from a mixture of xylene-ferrocene (99 at% C:1 at% Fe) inside a quartz tube reactor operating at approximately 700 degrees C. In a similar process, approximately 3 g of melamine (C3H6N6) was introduced during the growth of MWNTs to prepare nitrogen-doped nanotubes. The structural and electronic properties of nitrogen-doped MWNTs were determined by scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and thermopower measurements. The individual nitrogen-doped nanotube exhibits a bamboo-like structure and comprises 6-16 tube walls, as evidenced by HRTEM studies. The EELS measurements yielded an average nitrogen content of approximately 5 at% in the doped tubes. The thermoelectric power data of nitrogen-doped MWNTs remained negative even after exposure to oxygen for an extended period of time, suggesting that nitrogen doping of MWNTs renders them n-type, consistent with scanning tunneling spectroscopic studies on similar nanotubes.
authors.affiliation: Department of Physics and Astronomy, Clemson University, Clemson, South Carolina, USA.
authors.forename: B
authors.initials: B
authors.lastname: Sadanadan
authors.forename: T
authors.initials: T
authors.lastname: Savage
authors.forename: S
authors.initials: S
authors.lastname: Bhattacharya
authors.forename: T
authors.initials: T
authors.lastname: Tritt
authors.forename: Alan
authors.initials: A
authors.lastname: Cassell
authors.forename: M
authors.initials: M
authors.lastname: Meyyappan
authors.forename: Z R
authors.initials: ZR
authors.lastname: Dai
authors.forename: Z L
authors.initials: ZL
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: Zidan
authors.forename: A M
authors.initials: AM
authors.lastname: Rao
mesh_terms: D003460:Crystallization / Q000379:methods*; D004553:Electric Conductivity; D004563:Electrochemistry / Q000379:methods; D046911:Macromolecular Substances; D008422:Materials Testing / Q000379:methods; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000302:isolation & purification; D009584:Nitrogen / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D037742:Nanotubes, Carbon; D009584:Nitrogen