Functional Oxide Materials

Functional Oxide Materials

Solutions of nanoparticles (quantum dots) with different size. Solution colour depends on particle size.
Solutions of nanoparticles (quantum dots) with different size. Solution colour depends on particle size.

The field of application for oxidic inorganic materials has increased within the last decades. Espacially the fields of sensors and catalysts is coming into the focus for these type of materials because of their unique electronical, chemical and mechanical properties. Here the defined band gaps, high temperature resistivity as well as the oxidation stability are just a few characteristics making these class of materials a high potential candidate for new types of electronic components. Actually the most investigated types of oxides are titania, india, ceria, zirconia and zincoxide.

The fabrication of such materials can be achived by classical sol gel chemistry or by high temperature chemical vapour deposition steps. Hereby materials preparation is not focused on the materials itself but the main goal is a control of its morphology. It is known that the dimensions of such materials are responsible for mechanical and electronical properties. Therefore a morphological control in the preparation process is essential to produce materials with defined properties, as there are i.e. uniform band gaps. One example for such a feature is the colour of nanoparticles. The colour of a particle is depending on the size of its band gap, which itself is depending on the size of the particle.

SEM micrograph of nanostructured Ceria fibers for catalytic applications.
SEM micrograph of nanostructured Ceria fibers for catalytic applications.

Our research activities in the field of functional oxides are focused on catalytic characteristics of nanostructured materials, as well as the development of new materials for electronic components.

In the field of catalysis we are interested in synthesis of nanostructured materials of ceria, titania and copper oxide. Here we are not concentrated on the development of the catalytic process itself, but on the relationship of catalytic activity and morphology. Therefore different types of nanoscaled structures like fibers, 1D rods and particles are under investigation. Catalytic activity can be activated using nanoscaled materials beginning with very low temperatures compared with bulk material. Therefore a control of materials morphology can be part of green development.

Schematic sketch of n-type FET with open channel. (on state)
Schematic sketch of n-type FET with open channel. (on state)

Our research activities for development of electronic components are focused on zirconia, india, titania and zinc oxide. Here also the relationship between morphology and materials properties are of particular importance. The electrical conductance of inorganic oxides are dramatically influenced by the cristalinity and morphology of used materials. The conductivity is a central point in the development of electronical parts. The better the conductivity, the faster is the movement of electrons. This is a central point in the development of i.e. field effekt gtransistors (FETs). FETs are more and more important for microelectronic applications in real life. Therefore an investigation of such materials for faster switching and electron mobility plays an important roll for upcomming applications.

Publications

  • Adv. Mater. (2008), 20, 3383-3387.
  • Carbon (2009), doi: 10.1016/j.carbon.2009.07.034.
  • J. Mater. Chem. (2009), 19 , 5039-5046.
  • Eur. J. Inorg. Chem. (2009), doi:10.1002/ejic.200801239.
  • Ceramics Science and Technology (Vol 1): Structures ,VCH-Wiley, (2008).
  • Nanotechnology (Vol.1): Principles and Fundamentals ,VCH-Wiley, (2008), 97-138.