Influence of Fe/Cr on nitrogen doped carbon nanotube growth C. P. Ewels, A. Gloter, T. Minea, B. Bouchet-Fabre, S. Point and C. Colliex Eur. Phys. J. Appl. Phys., 42 3 (2008) 247-250 Published online: 30 April 2008 DOI: 10.1051/epjap:2008060