Michigan Technological University
Department of Physics

is pleased to announce a colloquium

with

Doug Lowndes

Scientific Director
Center for Nanophase Materials Sciences
http://cnms.ornl.gov/
Oak Ridge National Laboratory

Catalytically Controlled Growth and Assembly of Vertically Aligned Carbon Nanofibers: Basic Studies and Nanotechnology Applications

Vertically aligned carbon nanofibers (VACNFs) are structurally quite imperfect in comparison with single- or multi-wall carbon nanotubes, but their synthesis is highly controllable. Using a DC plasma-enhanced chemical vapor deposition (PECVD) method, VACNFs can be precisely positioned individually or in large arrays. VACNFs grow simultaneously by two mechanisms, catalytically controlled vertical growth and defect-mediated lateral growth, so their morphology can be varied via the relative growth rates. The vertical alignment of CNFs relative to the substrate is governed by the direction of the local plasma electric-field lines, so that deliberately tilted or kinked CNFs can be grown under certain conditions. Recent extensions to grow VACNFs using radio frequency (RF) PECVD and from nanometer-scale metal catalyst particles also will be described. An older growth model, and a quite new one, will be discussed and compared with experimental results. Finally, some potential nanotechnology applications of VACNFs will be described, including multi-electrode vacuum nanoelectronic devices using electron beams field-emitted from VACNF cathodes; tubular nanopipes formed using VACNFs as templates; and the use of VACNFs as an intracellular interface for monitoring phenomena and/or controlled biochemical manipulation within viable cells.

Biography

Doug Lowndes is Scientific Director of the new Center for Nanophase Materials Sciences that is currently under construction at Oak Ridge National Laboratory (ORNL). He also leads the Thin Film and Nanostructured Materials Physics group in ORNL’s Condensed Matter Sciences Division. Doug’s current research interests include growth and applications of carbon nanofibers and nanotubes; growth and properties of multilayered electronic oxide thin-film structures; and, energy-related applications for nanoscale materials and technology. He has authored or co-authored more than 290 articles in refereed journals and books, including a number of invited papers and reviews. From 1986-2000 Doug served as professor of materials science and engineering at the University of Tennessee-Knoxville, where he taught graduate and undergraduate courses in electronic materials and thin-film growth and supervised graduate student research. Prior to that he taught and conducted research in physics at the University of Oregon.

Doug is a Fellow of the American Physical Society and was appointed a Corporate Fellow of ORNL in 1994. In 1999-2000 he served as Chairperson of the Nanoscience/Nanotechnology Group for the Department of Energy’s Basic Energy Sciences (BES) program, as well as editing and contributing to that group’s report on Nanoscale Science, Engineering and Technology Research Directions (1999). In 2001 he was honored by ORNL with an R&D Leadership Award “for his innovative leadership in the development of nanoscale science research and related capabilities at ORNL.”

Thursday, April 29, 2004

4:00 p.m., Fisher 139

Refreshments will be served

MTU | Physics | Colloquium