Welcome to the web site for the Thin Film and Nanostructured Materials Physics Group, Condensed Matter Sciences Division at Oak Ridge National Laboratory. Our research currently addresses two broad scientific challenges, as described below. For detailed examples of our work please see the Research and Personnel pages.
Research on Nanomaterials: Controlled Synthesis and Properties
This research addresses the central challenge of nanoscale science: 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. The materials focus currently is on carbon nanotubes/nanofibers and on mesoscale oxide films/multilayers for greatly improved ionic conductivity. Part of the research addresses a grand challenge of nanomaterials synthesis: the growth of macroscopic single wall carbon nanotube (SWNT) crystals, and is carried out in collaboration with Rice University. 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. For synthesis, energetic-beam methods of pulsed laser deposition (PLD), laser vaporization (LV), supersonic chemical beams, and plasma-enhanced chemical vapor deposition (PECVD) are used, together with thermal CVD. A complete suite of time-resolved, in situ diagnostic methods is used to obtain information about the precursor species, temperatures, products, and dynamics of growth in these environments. For ex situ characterization, the program particularly exploits unique ORNL Z-STEM/EELS transmission electron microscopy and spectroscopy to determine structure and composition, now with atomic resolution through aberration correction. This research also involves strong multidisciplinary collaborations with other ORNL and university investigators.
Research on the Emergence of Nanoscale Cooperative Phenomena
This research addresses one of the most important scientific themes of our time, the fundamental and practical importance of understanding complex, self-organizing behavior. Its materials focus is on transition metal oxides (TMOs) and ferroelectric oxides, with special interest in electronically highly correlated materials that exhibit spontaneous electronic phase separation on the meso- to nano-scale. Their astonishing range of properties is believed to result from a variety of possible ground states that lie close together in energy, so that small changes can create new phenomena. The objective is to understand and control such effects in order to design artificially structured TMOs with new combinations of properties. This group's effort is part of a larger ORNL program that integrates three key capabilities: advanced synthesis, detailed characterization (nanoscale to bulk), and theoretical modeling and simulation. For synthesis we have assembled the tools and skills needed to study nanoscale interactions between different electronic phases in 3D (thick or coupled films), 2D (isolated thin layers and superlattices), and quasi-1D (quantum nanowires). For characterization an arsenal of ORNL scanning probe, electronic, magnetic, and transport properties measurements is used, together with Z-contrast scanning transmission electron microscopy (Z-STEM) and electron energy loss spectroscopy (EELS). Aberration-corrected Z-STEM/EELS now permits “seeing” how electronic properties vary, locally and quantitatively, across compositional interfaces, with atomic resolution. For theory, the high-performance computing facilities of ORNL’s Center for Computational Sciences (CCS) are employed together with collaborations between in-house and external theorists, to develop computational approaches suitable for nanoscale highly correlated electronic systems.
Research Impact
The impact of understanding self-organizing behavior, and of finding ways to further direct assembly to make exotic nanoscale properties useful at the macroscale, clearly will be enormous. There undoubtedly are general rules of controlled synthesis and directed assembly to be discovered, and the systematic application of these will result in the addition of many different nanostructured materials to our toolbox. Each success in directed assembly of nanomaterials will make available a new subset of engineering materials, and we know from centuries of experience that the discovery and development of advanced materials always have been the source of new technology.
Research on Nanomaterials: Controlled Synthesis and Properties
This research addresses the central challenge of nanoscale science: 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. The materials focus currently is on carbon nanotubes/nanofibers and on mesoscale oxide films/multilayers for greatly improved ionic conductivity. Part of the research addresses a grand challenge of nanomaterials synthesis: the growth of macroscopic single wall carbon nanotube (SWNT) crystals, and is carried out in collaboration with Rice University. 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. For synthesis, energetic-beam methods of pulsed laser deposition (PLD), laser vaporization (LV), supersonic chemical beams, and plasma-enhanced chemical vapor deposition (PECVD) are used, together with thermal CVD. A complete suite of time-resolved, in situ diagnostic methods is used to obtain information about the precursor species, temperatures, products, and dynamics of growth in these environments. For ex situ characterization, the program particularly exploits unique ORNL Z-STEM/EELS transmission electron microscopy and spectroscopy to determine structure and composition, now with atomic resolution through aberration correction. This research also involves strong multidisciplinary collaborations with other ORNL and university investigators.
Research on the Emergence of Nanoscale Cooperative Phenomena
This research addresses one of the most important scientific themes of our time, the fundamental and practical importance of understanding complex, self-organizing behavior. Its materials focus is on transition metal oxides (TMOs) and ferroelectric oxides, with special interest in electronically highly correlated materials that exhibit spontaneous electronic phase separation on the meso- to nano-scale. Their astonishing range of properties is believed to result from a variety of possible ground states that lie close together in energy, so that small changes can create new phenomena. The objective is to understand and control such effects in order to design artificially structured TMOs with new combinations of properties. This group's effort is part of a larger ORNL program that integrates three key capabilities: advanced synthesis, detailed characterization (nanoscale to bulk), and theoretical modeling and simulation. For synthesis we have assembled the tools and skills needed to study nanoscale interactions between different electronic phases in 3D (thick or coupled films), 2D (isolated thin layers and superlattices), and quasi-1D (quantum nanowires). For characterization an arsenal of ORNL scanning probe, electronic, magnetic, and transport properties measurements is used, together with Z-contrast scanning transmission electron microscopy (Z-STEM) and electron energy loss spectroscopy (EELS). Aberration-corrected Z-STEM/EELS now permits “seeing” how electronic properties vary, locally and quantitatively, across compositional interfaces, with atomic resolution. For theory, the high-performance computing facilities of ORNL’s Center for Computational Sciences (CCS) are employed together with collaborations between in-house and external theorists, to develop computational approaches suitable for nanoscale highly correlated electronic systems.
Research Impact
The impact of understanding self-organizing behavior, and of finding ways to further direct assembly to make exotic nanoscale properties useful at the macroscale, clearly will be enormous. There undoubtedly are general rules of controlled synthesis and directed assembly to be discovered, and the systematic application of these will result in the addition of many different nanostructured materials to our toolbox. Each success in directed assembly of nanomaterials will make available a new subset of engineering materials, and we know from centuries of experience that the discovery and development of advanced materials always have been the source of new technology.
Nombre y Apellido: Juan J. Núñez C.
Asignatura: CRF
Sección: 01
Fuente: http://www.tnmp.ornl.gov/
Leer: [Ap22:14]
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