Various fitting procedures were used to study the Raman dispersion behavior of the G’-band in plasma-treated multi-walled carbon nanotubes. The analysis showed that the trend of the G’-band dispersion was related to the presence of defects in the multi-walled carbon nanotube. The intensity ratio dispersions involving the G21’, G32’, G41’ and G42’ components of the G-band behaved in a similar way to the well-known D to G band ratio (D/G), which was a good criterion for estimating the defect content in multi-walled carbon nanotubes. The G21’, G32’, G41’ and G42’ peaks were 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, G22’, G33’, G43’ and G44’ behaved like the G band and were related to the non-defect content. Consequently, the intensity ratios, G21’/G22’, G32’/G33’ and G41+42’/G43+44’ exhibited the same dispersion behavior as that of D/G. The difference of band position between the high and low frequency G’-band components was found to be sensitive to the plasma treatment.

Comparison of Fitting Procedures in the Study of Plasma-Induced Defect Formation in Carbon Nanotubes. S.Lee, J.W.Peng: Physica Status Solidi B, 2011, 248[7], 1645-50