Single-wall carbon nanotubes (SWCNT) can be produced using different processes, including arc discharge, laser ablation,   CVD and plasma enhanced CVD. The SWCNT investigated in this study were grown by catalytic CVD (CCVD). The CCVD method represents the most suitable technique for nanoelectronic devices applications and for CNT-polymer nanocomposites deposited as conductive thin films electrodes. The samples were prepared by dilution and sonication for different time ( 30 min., 1h and 1h3min.) of powders in order to obtain thin films on glass substrate by slow evaporation of the solvent. The Raman spectra in the 50-2500 cm-1 wavenumber range and images were obtained with 632 nm laser excitation through a confocal microscope. The spectra at each image point are the average of 4 s integration acquired through a 100x, 0,9 NA (numerical aperture) objective. The Raman spectra for all sample show a prominent multi-peaks ( line intensity>25 000 cnt.) located around 1580 cm-1 which is identified as G mode (or TM) and corresponds to the stretching of the -C-C- bond in the graphite plane. Different G band peaks depend on the electronic properties - semiconducting -G+ at 1592 cm-1 and metallic G- at 1550 cm-1 due to the presence of free electrons. The radial breathing mode (RBM) in low frequency region, 50 -300 cm-1 ( line intensity>4000 cnt.), associated of at. vibration of C atoms in radial direction is correlated linearly with the reciprocal of nanotube diameter. An estimated value of SWCNT diameter was about 2 nm which are confirmed by ultra-high resolution FEG-SEM images. The D Raman band which is observed at 1340 cm-1 (line intensity>1000 cant.), is activated in the first order scattering process of sp2 carbon by the presence of in- plane substitutional hetero-atoms, vacancies or other defects. The D band is attributed to the disorder-induced vibration and the low value (below one) of D/G peak ratio implies the formation of good quality nanotubes.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/19321 must be provided.

1. Metal-semiconductor-metal photodetector on silicon on insulating wafers based on nanoscale interdigitated electrodes E. Budianu, M. Purica, A. Dinescu, E. Manea
2. Polymers doped with metal oxide nanoparticles with controlled refractive index