Experimental evidence for the early nucleation of single-walled carbon nanotubes

In situ optical emission spectroscopy (OES) was used to investigate the spatial and temporal evolution of C 2 , the electron density ( N e ) and the electron temperature ( T e ) of laser induced plasmas in the laser-furnace method of synthesizing single-walled carbon nanotubes (SWCNTs). The intensities of the spectral maps of C 2 , N e and T e showed a strong temperature dependence. The frequency of sharp fluctuations which appear as hot spots in the spectral maps of N e and T e increased as the furnace temperature was increased from 1073 to 1273 K. We suggest that the appearance of hot spots is a result of the heat of formation of SWCNTs.