Product Code: ICA12_N201

Nonequilibrium Laser Synthesis and Real-Time Diagnostics of Carbon Nanomaterial Growth - Invited Presentation - 30 Minutes
Authors:
David B. Geohegan, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory; - USA
Alex A. Puretzky, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory; Oak Ridge
Christopher M. Rouleau, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory; Oak Ridge
Murari Regmi, Materials Science and Engineering Division, Oak Ridge National Laboratory; Oak Ridge
Jeremy J. Jackson, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory; -
Jason D. Readle, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory; -
Karren More, Shared Research Equipment Facility, Oak Ridge National Laboratory; Oak Ridge
Gyula Eres, Materials Science and Engineering Division, Oak Ridge National Laboratory; Oak Ridge
Gerd Duscher, Department of Materials Science and Engineering, Univ. of Tennessee; Oak Ridge
Presented at ICALEO 2012

Lasers provide not only unique growth conditions for the synthesis of novel nanomaterials but they can serve as remote spectroscopic probes of the growth environment. Ultimately, they can act as real-time diagnostics to control the nanomanufacturing of nanomaterials. Here, progress in the laser-based synthesis and investigations of carbon nanomaterial growth kinetics will be reviewed with an emphasis on single-wall carbon nanotubes (SWNTs), single-wall carbon nanohorns (SWNHs), and graphene. Two synthesis methods will be compared. First, the unique high-temperature growth environment of a laser plasma will be examined using time-resolved imaging and laser spectroscopy to understand how pure carbon can self-assemble rapidly into a variety of forms including SWNHs and graphene flakes, and with catalyst-assistance, SWNTs. Atomic resolution images of SWNTs, SWNHs, and graphene reveals that graphene flakes are likely building blocks for the growth of these materials. Second, lower-temperature, chemical vapor deposition (CVD) methods suitable for mass production of nanomaterials will be examined. Pulsed-CVD and pulsed laser deposition (PLD) are described to investigate the catalyst-assisted growth kinetics of graphene and SWNTs. Time-resolved laser reflectivity and Raman spectroscopy studies show that autocatalytic kinetics imply the existence of intermediates crucial to the efficient nanomanufacturing of these materials for energy applications.