Effect of the manufacturing parameters on the structure of nitrogen-doped carbon nanotubes produced by catalytic laser-induced chemical vapor deposition

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2013-11, Vol.15 (11), p.1-11, Article 2045
• Main Authors: Morjan, Iuliana P., Alexandrescu, Rodica, Morjan, Ion, Luculescu, Catalin, Vasile, Eugeniu, Osiceanu, Petre, Scarisoreanu, Monica, Demian, Gabriela
• Format: Article
• Language: English
• Subjects: Ammonia; Bamboo; Catalytic methods; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Inorganic Chemistry; Lasers; Materials Science; Methods of nanofabrication; Nanocrystalline materials; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanotechnology; Nanotubes; Nitrogen; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Radiation effects on specific materials; Research Paper; Spectroscopy; Structure of solids and liquids; crystallography
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-013-2045-z

Nitrogen-containing carbon nanotubes (CNx-NTs), with a relatively high level of nitrogen doping were prepared by the catalytic laser-induced CVD method. The nanotubes were catalytically grown directly on a silicon substrate from C 2 H 2 /NH 3 gaseous precursors. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) give firm evidence for the nitrogen doping. As determined by XPS, the N concentration for the prepared CNx-NTs increases from 3.6 to 30.6 at.% with increasing ammonia concentration and pressure. TEM images indicate that the nanotubes are bamboo like. As the nitrogen content increases, there is a transition from the bamboo shape with few defects and little distortion to a corrugated structure with a much larger number of defects. Raman spectroscopy revealed that with increasing nitrogen concentration, there is more disorder and defects, together with an increase in I D / I G ratio. By energy-filtering TEM, a higher N concentration was found on the outer amorphous nanolayer than in the compartment core of the nanotubes.