Functional oxide aperiodic superlattices
Event details
| Date | 28.11.2014 |
| Hour | 11:00 |
| Speaker | Prof. Velimir Radmilovic, Nanotechnology and Functional Materials Center, Faculty of Technology and Metallurgy, University of Belgrade |
| Location | |
| Category | Conferences - Seminars |
Functional oxide nanowires are expected to play an important role in scavenging waste heat and converting it into electricity. Some complex superlattices in hetrostructures contain periodic compositional and structural features, typically on the nanometer scale, making them promising materials for thermoelectric applications.
In this presentation, I will discuss our recently discovered a novel method to produce M2O3(ZnO)n aperiodic superlattice nanowires (M=In, Ga, Fe,..) by solid state diffusion process. This is in agreement with the theoretical prediction that it is possible to increase the material-dependent figure of merit, zT, by using low dimensional materials, attributed to electronic band structure changes and enhanced interface phonon scattering. Atomic resolution HAADF imaging is used to perform a detailed structural analysis on the M2O3(ZnO)n nanowires, unambiguously determined the location of indium within the structure and to evaluate lattice strain and the presence of defects. Based on this analysis we propose that the superlattice structure is generated through a defect-assisted process.
One of the greatest advantages of this novel synthesis is the ability to tune the nanoscale features of the polytypoid wires by simply adjusting the amount of metal precursor. We also performed a quantitative analysis of the change in superlattice inclusion density and periodicity with metal deposition. Compare to ZnO nanowires, these new oxide thermoelectric nanostructures exhibited almost three orders of magnitude increase in efficiency. This will enable future studies on structure-dependent thermoelectric properties and possibly lead to further enhancements in thermoelectric efficiency.
Bio: Velimir Radmilovic was born in 1948 in Herceg Novi, Montenegro. He graduated from the Faculty of Technology and Metallurgy (TMF), University of Belgrade, in 1972. He got his MSc (1981) and PhD (1985) degree in Physical Metallurgy, TMF, University of Belgrade. Dr. Radmilovic got a position of an assistant professor in Physical Metallurgy from the TMF in Belgrade in 1985, associate professor in 1991, and full professor in 1995. He has been teaching numerous undergraduate and graduate courses related to materials science and physical metallurgy such as: physical metallurgy, phase transformations, crystallography and crystal defects, X-ray diffraction, electron microscopy, mechanical metallurgy, and heat treatment. He is the author or coauthor of 143 scientific papers published in peer review journals in the field of physical metallurgy, materials science, nanoscience and nanotechnology and 222 papers published in conference proceedings and presented at national and international conferences. His results were cited in the scientific literature more than 1000 times. As a visiting professor and a research fellow he worked at the Department of Materials Science, University of California at Berkeley, University of Pittsburgh, Pennsylvania, and National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, where he is currently principal investigator. He has been serving as a reviewer to numerous peer review journals such as Metallurgical and Materials Transaction, Materials Science and Engineering, Science, Nanotechnology, Acta Materialia, Scripta Materialia, Diamond and Related Materials, Journal of Materials Science, Journal of Serbian Chemical Society
In this presentation, I will discuss our recently discovered a novel method to produce M2O3(ZnO)n aperiodic superlattice nanowires (M=In, Ga, Fe,..) by solid state diffusion process. This is in agreement with the theoretical prediction that it is possible to increase the material-dependent figure of merit, zT, by using low dimensional materials, attributed to electronic band structure changes and enhanced interface phonon scattering. Atomic resolution HAADF imaging is used to perform a detailed structural analysis on the M2O3(ZnO)n nanowires, unambiguously determined the location of indium within the structure and to evaluate lattice strain and the presence of defects. Based on this analysis we propose that the superlattice structure is generated through a defect-assisted process.
One of the greatest advantages of this novel synthesis is the ability to tune the nanoscale features of the polytypoid wires by simply adjusting the amount of metal precursor. We also performed a quantitative analysis of the change in superlattice inclusion density and periodicity with metal deposition. Compare to ZnO nanowires, these new oxide thermoelectric nanostructures exhibited almost three orders of magnitude increase in efficiency. This will enable future studies on structure-dependent thermoelectric properties and possibly lead to further enhancements in thermoelectric efficiency.
Bio: Velimir Radmilovic was born in 1948 in Herceg Novi, Montenegro. He graduated from the Faculty of Technology and Metallurgy (TMF), University of Belgrade, in 1972. He got his MSc (1981) and PhD (1985) degree in Physical Metallurgy, TMF, University of Belgrade. Dr. Radmilovic got a position of an assistant professor in Physical Metallurgy from the TMF in Belgrade in 1985, associate professor in 1991, and full professor in 1995. He has been teaching numerous undergraduate and graduate courses related to materials science and physical metallurgy such as: physical metallurgy, phase transformations, crystallography and crystal defects, X-ray diffraction, electron microscopy, mechanical metallurgy, and heat treatment. He is the author or coauthor of 143 scientific papers published in peer review journals in the field of physical metallurgy, materials science, nanoscience and nanotechnology and 222 papers published in conference proceedings and presented at national and international conferences. His results were cited in the scientific literature more than 1000 times. As a visiting professor and a research fellow he worked at the Department of Materials Science, University of California at Berkeley, University of Pittsburgh, Pennsylvania, and National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, where he is currently principal investigator. He has been serving as a reviewer to numerous peer review journals such as Metallurgical and Materials Transaction, Materials Science and Engineering, Science, Nanotechnology, Acta Materialia, Scripta Materialia, Diamond and Related Materials, Journal of Materials Science, Journal of Serbian Chemical Society
Practical information
- Informed public
- Free
Organizer
- ICMP (Arnaud Magrez and Raphaël Butté)