Pulsed Nd:YAG laser heating and treatment on multi-walled carbon nanotubes film

Multi-walled carbon nanotubes (MWCNTs) film surface was flashed with the second harmonic (λ = 532 nm) of a single pulse of Nd:YAG laser in air, vacuum (0.03Pa) and nitrogen. When MWCNTs film is irradiated with a pulsed Nd:YAG laser of 23.7 mJ/cm2, the calculated value of maximum surface temperature becomes 304 oC. The surface temperature increases from 595 oC to 2968 oC with the increase of laser power from 59.4 mJ/cm2 to 469 mJ/cm2. MWCNTs film was examined by Raman spectroscopy to clarify the effect of Pulsed Nd:YAG laser heating. Raman spectra of MWCNTs films before and after irradiation were measured. The intensity of the two characteristic Raman shifts ID (defect-induced mode: D-band) and IG (graphite-induced mode: G-band) was examined. Moreover, IG/ID ratio and normalized D-band FWHM (Full Width at Half Maximum) of MWCNTs film were measured from Raman spectra and compared with the calculated results of maximum temperature of MWCNTs film surface. The purification and graphitization of as-prepared MWCNTs occurred after irradiation.