Synthesis of carbon nanotubes by laser-assisted chemical vapor deposition

With recent advances in the aligned growth of carbon nanotubes (CNTs), there are great interests in CNT-based field-emission and electronic applications. In conventional thermal chemical vapor deposition, substrates as well as chambers need to be globally heated to a sufficiently-high reaction temperature. In this paper, we report a method for direct synthesis of CNTs on pre-defined electrodes using laser-assisted chemical vapor deposition. A CW CO2 laser (wavelength 10.6 mu m, beam diameter 2 mm) was used to irradiate the pre-defined structures for CNT growth. The temperature of the substrate was measured by a pyrometer, ranging from 850-1000 degrees C. By varying catalysts and laser parameters, carbon nanostructures including carbon nanofiber, multi-walled and single-walled CNTs can be controllably synthesized.