Spectroscopic Characterization of N-Doped Single-Walled Carbon Nanotube Strands: An X-ray Photoelectron Spectroscopy and Raman Study

We have studied in detail the carbon and nitrogen bonding environments in nitrogen-doped single-walled carbon nanotubes (SWCNTs). The samples consisting of long strands of N-doped SWCNTs were synthesized using an aerosol assisted chemical vapor deposition method involving benzylamine-ethanol-ferrocene solutions. The studied samples were produced using different benzylamine concentrations in the solutions, and exhibited a maximum concentration of ca. 0.3%at of N, determined by X-ray photoelectron spectroscopy (XPS). In general, we observed that the ratio between substitutional nitrogen and the pyridine-like bonded nitrogen varied upon the precursor composition. Moreover, we have observed that the sp(2)-like substitutional configuration of the C-N bond does not exceed the 50% of the total N atomic incorporation. In addition, we have characterized all these samples using Raman spectroscopy and electron microscopy.