Laser for carbon nanotubes: From the PLD deposition of the catalytic layer to the thermal characterization by nanosecond pulsed laser

Abstract

Carbon nanotubes (CNTs) are grown with a three steps process during which the sample is kept under vacuum combining pulsed laser deposition and radio frequency plasma enhanced chemical vapor deposition techniques. As results, the obtained CNTs are densely grown and vertically aligned, multi-walled, 5 to 20 nm in outer diameter. TEM analyses show the well graphitized parallel walls. Catalyst nanoparticles are trapped within or along the body of the CNTs. To characterize their thermal properties by pulsed photothermal method, it is necessary to deposit on the top a metallic thin layer (Ti, about 200 nm) acting as a photothermal transducer. The thermal conductivity and volumetric heat capacity of the CNTs film are identified. They are found to be respectively 210Wm−1K−1 and 5×104JK−1m−3.