During the catalytic chemical vapor deposition (CCVD) of carbon nanotubes (CNTs) the gas phase has been investigated by applying linear Raman spectroscopy and particle image velocimetry (PIV) in a specially designed cold wall reactor. Via PIV the impingement of the feed flow onto the hot Si-wafer could be characterized by determining the flow field. Through the Raman experiments, it was possible to measure in situ the acetylene conversion as well as the temperature progress over reaction time. Furthermore, a concept has been developed for the simultaneous analysis of the gas and the solid phase during the CCVD of CNTs. This makes possible the simultaneous in situ measurement of the gas phase composition, the gas phase temperature and the characteristics of the growing CNTs with a high temporal and spatial resolution, such that these comprehensive investigations can provide a sustained understanding of the CNTs nucleation and growth mechanism, which for the first time consider the intermediate reaction steps taking place inside the reactor.
Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2012: Advanced Materials, CNTs, Particles, Films and Composites (Volume 1)
Published: June 18, 2012
Pages: 273 - 277
Industry sector: Advanced Materials & Manufacturing
Topics: Carbon Nano Structures & Devices