Delivered by Ingenta to: Universitaet Bayreuth IP : 132.180.124.134 Fri, 12 Oct 2012 10:27:13 RESEARCH ARTICLE Copyright © 2012 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Nanoelectronics and Optoelectronics Vol. 7, 95–98, 2012 Diagnostics of Carbonaceous Nanomaterial “Taunit” by Raman Spectroscopy O. A. Maslova 1 * , A. S. Mikheykin 1 , I. N. Leontiev 1 , Yu. I. Yuzyuk 1 , and A. G. Tkachev 2 1 Faculty of Physics, Southern Federal University, Zorge Street 5, 344090, Rostov-on-Don, Russia 2 Tambov State Technical University, Leningradskaya Street 1, Tambov, Russia Crystalline structure perfection of carbonaceous nanomaterial (CNM) “Taunit” which constitutes the multi-walled nanotubes was studied using a Raman spectroscopy technique. CNM “Taunit” was synthesized by MOCVD method. The pristine material, the samples annealed at different temper- atures and the samples functionalized by Pt-catalyst nanoparticles were investigated. It has been found that “Taunit” belongs to the poorly organized carbon materials but its crystalline structure was observed to order while the annealing temperature increased. D1 and G Raman band (at 1350 and 1580 cm -1 , respectively) intensity ratios were calculated to estimate the crystal structure ordering of CNM “Taunit”. The investigation of the influence of functionalization by the catalyst nanoparticles shows that Pt-catalyst precipitation on the surface of MWNTs leads to the increase of the defect band intensity due to an appearance of lattice defects. Keywords: Multi-Walled Carbon Nanotubes, Raman Spectroscopy, Crystalline Structure Order- ing, D- and G-Band Intensities Ratios, Pt-Catalyst Nanoparticles. 1. INTRODUCTION Carbon Nanotubes (CNTs) have unique structure and show remarkable properties that make them potentially useful in many applications in nanotechnology, electronics, optics and many fields of materials science. CNTs and nanofibers are usually used for a design of composite materials with a high electric conductivity, a thermal conductivity and a strength. CNTs embedded into the polymers improve their properties. Single- and multi-walled carbon nanotubes are prospective materials for the electron emitters, superca- pacitors, electrochemical catalyst-carriers used in the low- temperature fuel cells. Due to such unusual optical properties as a combina- tion of a high nonlinearity with a high damage threshold these structures are attractive for the integrated photonic and electronic devices. CNTs exhibit a strong saturable absorption, i.e., they become transparent under the suf- ficiently intense light elimination. It is easy to tune the saturable absorption in a broad optical range by varying the nanotube diameter for telecommunications, medicine and photonics. CNTs also have the sub-picosecond relax- ation times and thus they are ideal for an ultrafast photonics. * Author to whom correspondence should be addressed. A carbonaceous nanomaterial (CNM) “Taunit” is a set of nanofibers with a length of 2 and more m and an external diameter varying from 15 to 40 nm. In accor- dance with the classification proposed by Rakov 1 “Taunit” constitutes the multi-walled nanotubes mainly with the conic shape graphene layers. Due to such remarkable prop- erties as a chemical and thermal stability, a sufficient strength, a high electric conductivity and a cool electron emission ability this material is promising for applica- tion in photonics and electronic devices, pharmaceutics, electric conductivity polymeric composites and hydrogen accumulators. 2 The aim of this paper is to study the crystalline structure ordering of CNM “Taunit” by a Raman spectroscopy tech- nique. The Raman spectroscopy is an effective method for investigation of single- and multi-walled carbon nanotubes and nano- and microcrystalline graphite, 3–6 because the Raman signals of graphite crystals result from the lattice vibrations and are very sensitive to the degree of a struc- tural disorder. 7 So we have investigated the applicability of the Raman spectroscopy for the structural characterization of CNM “Taunit” by the systematic experiments and the spectral analysis. The Raman spectra of a pristine mate- rial “Taunit”, the samples annealed at different tempera- tures and the samples functionalized by Pt-nanoparticles were studied. J. Nanoelectron. Optoelectron. 2012, Vol. 7, No. 1 1555-130X/2012/7/095/004 doi:10.1166/jno.2012.1225 95