Laser irradiation of carbon nanotubes

We report on the structural modifications of carbon nanotubes (CNT) by lase r irradiation. In particular, we investigated the transformation of CNT by using Nd:YAG laser operating at 266 and 1064 nm with different energy fluen ces and number of pulses. After 15 pulses of 266 mn laser irradiation with a laser fluence of 80 and 60 mJ cm(-2), transformation of CNT into sub-micr on size plates and cauliflower type aggregation of carbon deposits, respect ively, were observed. At a fixed laser fluence of 400 mJ cm(-2) (1064nm) tr ansformation of CNT into carbon mass protrusions with progressive sharper a spect ratio was obtained by increasing number of laser pulses. Our investig ations demonstrate that a selective area transformation can be controlled b y the laser fluence and number of pulses. (C) 2001 Elsevier Science B.V. Al l rights reserved.