Characterization of fullerene-like CNx thin films deposited by pulsed-laser ablation of graphite in nitrogen
2004; Wiley; Volume: 201; Issue: 10 Linguagem: Inglês
10.1002/pssa.200304903
ISSN1521-396X
AutoresHenry Riascos, G. Zambrano, P. Prieto, A. Devia, H. Galindo, Chrystian Power, J. Gonz�lez,
Tópico(s)Laser-Ablation Synthesis of Nanoparticles
ResumoFullerene-like CNx thin films were synthesized by Pulsed-Laser Ablation (PLA) of pyrolythic graphite (99.99%) target in nitrogen using a (500 mJ, 7 ns, 1064 nm) Nd:YAG-pulsed laser. The films were deposited onto silicon substrates at 300 °C and nitrogen pressures within the 5–100 mTorr range. The composition and structure of these films were analyzed by means of Reflection Absorption Infrared Spectroscopy (RAIRS), XPS, and Raman spectroscopy and the morphology of the film surfaces by AFM. The RAIRS analysis of films deposited at different pressures shows the presence of the 2229 and 2273 cm–1 stretching peaks associated to CN triple bonds (C≡N) of nitriles and isocyanides. On the other hand, the XPS study of the N 1s bonding energy region provided typical spectra of the CNx materials. The spectra present the energy peaks at 400.8 (P2) and 398.4 eV (P3), which are usually assigned to nitrogen that is bonded to sp2 and sp3-coordinated C atoms, respectively. For a fullerene-like structure with developed basal planes, nitrogen is mostly bonded in a sp2-rich environment. In our conditions, in films deposited at 5 mTorr the P2/P3 ratio is 1.41 indicating a fullerene-like structure. Finally, the Raman analysis of films produced at different pressures, shows the characteristic D and G peaks at 1360–1370 cm–1 and 1580–1590 cm–1 related to the bond length in sp3 or sp2-coordinated carbon respectively. The study demonstrated that laser ablation technique, by using an Nd:YAG-pulsed laser, is a viable technique for the growth of fullerene-like CNx films. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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