FWI Institutskolloquium: "Tailored and tunable properties of nanostructures"

Datum

27.10.2011

Zeit

10:30 - 12:00

Sprecher

Prof. Dr. Horst Hahn, Karlsruhe Institute of Technology (KIT), Institute for Nanotechnology and Joint Research Laboratory Nanomaterials (KIT-TUD), Technische Universität Darmstadt

Sprache

en

Hauptthema

Physik

Andere Themen

Physik

Host

Susann Gebel (2345)

Beschreibung

The properties of materials are typically tailored by their micro- and nanostructure. This implies control of the grain size, defect concentration, structure and metastability. As long as the microstructure does not change during the use of the material, the properties of the material are fixed, or irreversible. As an example of materials with tailored properties, novel glass structures, so called nanoglasses, will be briefly presented. In contrast, in semiconducting materials, properties can be tuned by the application of an external field due to the space charge regions which extend far from the interfaces. In conducting systems, this effect cannot be observed unless the dimensions of the structures are in the nanometer regime. The reason for this different behavior is the small spatial dimension of the space charge regions due to the effective screening of the induced charges by the conduction electrons. Several examples of tuneable property changes for metal and oxide nanostructures in the form of thin films and nanoporous, nanoparticulate structures will be presented. The tuning can be either achieved by dielectric/ferroelectric gating, well known from semiconductor physics, or by electrochemical gating using liquid and solid electrolytes. As an example for tuneable magnetic properties, ferroelectric gating of LSMO-thin films and electrochemical gating of porous LSMO nanostructures will be discussed. A main focus of the presentation will be on the tuneable electrical conductivity of oxide nanoparticulate structures. The potential for applications in printable electronics based on the observation of a field effect behavior using electrochemical gating of ITO and Indium Oxide will be demonstrated.

Letztmalig verändert: 27.10.2011, 09:35:03