Nitrogen doped carbon nanotubes were grown on Fe2O3 nanoparticles deposited on silicon substrates, by laser-induced chemical vapour deposition of acetylene/ammonia mixtures. The concentration of the nitrogen has been controlled in the range 1-6 atomic% by adjusting the flow rate of ammonia, pressure and laser power. XPS and Raman spectroscopy were used to quantitatively assess the compositional and structural properties of the nitrogen-doped carbon nanotubes (N-CNTs). First order Raman spectra were deconvoluted assuming five vibrational modes and the integrated peak intensity ratio I-D/I-G and I-2D/I-G of all samples are displayed. We demonstrate that the relative amount of sp(2) C=C carbon has the same trend as I-D4/I-G and the pyrrolic relative amount exhibits the same trend as I-2D4/I-G. The high resolution TEM images are consistent with the Raman and XPS results, revealing that the surface of the N-CNTs outer walls becomes more distorted at the highest content of N while the inner walls of the nanotube preserve a high crystallinity, corresponding to the lowest ID/IG ratio. (C) 2017 Elsevier B.V. All rights reserved.