Welcome to the Thin Films and Nanostructures Group

Our research in the Thin Films and Nanostructured Materials Group focuses on the controlled synthesis of thin-film materials and nanostructures, as well as on the characterization of their functional properties and an understanding of how they relate to synthesis parameters.

Epitaxial perovskite films are obtained using pulsed-laser deposition (PLD) with in-situ
monitoring by Reflection High-Energy Electron Diffraction (RHEED), a process that allows us to synthesize artificially layered materials with
atomic-scale control. The emphasis of this work is understanding and controlling cooperative phenomena that emerge at the nanoscale and at interfaces (for example, obtaining interfacially-induced magnetism or electronic conduction); forming meta-stable oxides in which to explore novel physical properties; and studying the effects of strain and spatial confinement of ferroelectrics, magnetic oxides, and multiferroics. This effort is led by H.M. Christen and H.N. Lee.

The TFN group has a distinguished record in using real-time, in-situ diagnostic techniques to monitor growth processes. A unique opportunity to probe the crystallization and growth of perovskite materials in the PLD process is provided by the use of synchrotron surface x-ray diffraction (performed at the Advanced Photon Source). Real-time (microsecond resolution) observations of layer coverage and island size evolution shed light onto the very fast nature of the PLD process. This effort is led by G. Eres and C.M. Rouleau, in collaboration with B. Larson and J. Tischler.

The efforts led by D.B. Geohegan, Alex Puretzky, and G. Eres focus on the need for fundamental understanding of how nanomaterials grow and for control of the growth environment, in order to synthesize materials with new or greatly enhanced properties at attractive rates. A large fraction of this work focuses on carbon nanotubes/nanofibers, including the growth of large quantities of loose nanomaterials and the growth of vertically-aligned nanotube arrays. The program’s strength is its integration of three key capabilities: advanced synthesis; time-resolved, in situ diagnostics during growth; and an arsenal of nanomaterials properties measurement and functionalization methods.

In addition to pulsed-laser synthesis (oxides, carbon nanostructures) and chemical vapor deposition (CVD) of carbon nanotubes and related materials, a special effort is focused on the energetic beam growth of carbon-based materials, including carbon nanotubes and epitaxial diamond films (Contact: Gyula Eres).

The principal technical contact for discussing potential projects in the TFN Group is Dr. Hans M. Christen, Group Leader; tel. (865) 574-5965, e-mail christenhm@ornl.gov.