Comparison of fitting procedures in the study of plasma-induced defect formation in carbon nanotubes

• Published in: Physica Status Solidi (b) Vol. 248; no. 7; pp. 1645 - 1650
• Main Authors: Lee, Szetsen, Peng, Jr-Wei
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.07.2011; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Carbon nanotubes; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Criteria; Cross-disciplinary physics: materials science; rheology; Defects; dispersion relations; Dispersions; Exact sciences and technology; Fittings; Low frequencies; Materials science; Multi wall carbon nanotubes; MWCNT; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanotubes; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; plasma reactions; Raman spectra; Structure of solids and liquids; crystallography; Trends; Line intensity; Raman spectra; Line shape; Multiwalled nanotube; Dispersion relations; Plasma assisted processing; Carbon nanotubes; Confocal microscopy; Defect formation
• ISSN: 0370-1972; 1521-3951; 1521-3951
• DOI: 10.1002/pssb.201046467

We have adopted different fitting procedures to study the Raman dispersion behavior of the G′ band in plasma‐treated multi‐walled carbon nanotubes (MWCNTs). Our analysis shows that the trend of the G′ band dispersion is related to the presence of defects in the MWCNTs. The intensity ratio dispersions involving the $G'_{21} $, $G'_{32} $, $G'_{41} $, and $G'_{42} $ components of the G band behave in a similar way to the well known D to G band ratio ($D/G$), which is a good criterion for estimating the defect content in MWCNTs. The $G'_{21} $, $G'_{32} $, $G'_{41} $, and $G'_{42} $ peaks are shown to belong to the lower‐frequency components of the G′ band by using two‐, three‐, and four‐peak fitting procedures. Conversely, the higher‐frequency components $G'_{22} $, $G'_{33} $, $G'_{43} $, and $G'_{44} $ behave like the G band and are related to the non‐defect content. Consequently, the intensity ratios $G'_{21} /G'_{22} $, $G'_{32} /G'_{33} $, and $G'_{41 + 42} /G'_{43 + 44} $ show the same dispersion behavior as that of $D/G$. The difference of band position between the high and low frequency G′ band components is found to be sensitive to plasma treatment.