Raman study of single wall carbon nanotube thin films treated by laser irradiation and dynamic and isothermal oxidation

Abstract

The effect of visible and infrared irradiation on the structure of single wall carbon nanotubes (SWCNTs) is still an insufficiently resolved subject. In this paper, we report a detailed study of two types of SWCNT thin films treated by pulsed laser irradiation and dynamic and isothermal oxidation, respectively. Raman features of treated films were investigated by 532, 633 and 780 nm excitation lines, respectively. It was established that the 532 nm excitation laser line probes the surface of SWCNT films, while the two others probe the bulk of SWCNT films. It was found that during Raman measurements, one type of SWCNTs warms up significantly while the other type does not change temperature. Raman analysis of SWCNTs probed with 532 nm showed that effects of high power laser irradiation on two types of SWCNTs are completely different. Major effects are decomposition, debundlation and photooxidation. It was found that debundlation and removal of defective carbon are much more pronounced in one type of SWCNTs treated with dynamic oxidation. Dynamic oxidation affects mostly thinner SWCNTs that easily burn in air. The only significant effects of isothermal oxidation are the increase of defective amorphous carbon in the first type of SWCNTs and the decrease of D band and debundlation in the second type. Copyright © 2012 John Wiley & Sons, Ltd.