Place: Kleiner Physik-Hörsaal, Geschwister-Scholl-Platz
Date: 25.11.11, Time: 15:30 h
Properties and Applications of Nanoparticles (from the Gas Phase)
Prof. Axel Lorke
Fakultät für Physik und CeNIDE, Universität Duisburg-Essen
Particles with dimensions between 1 and 100 nm are affected by various size effects, which determine their electronic, optical, magnetic and thermal properties. On the one hand, it is a challenge for basic science to unravel the mechanisms underlying these size effects. On the other hand, the tunability of the material properties on the nanoscale is of interest for applied and engineering sciences. In this context, nanoparticles from the gas phase are particularly suitable, since they can be produced in large quantities and with excellent material quality.
In this talk, a few examples of nanoparticle-based systems and devices will be presented to illustrate the range of applications for tailored nanomaterials. A more in-depth view will be given into the intriguing optical properties of Silicon nanoparticles. While bulk Silicon is known to not exhibit light emission, nanoscale Si can show a bright, tunable photoluminescence in the visible spectral range, with a surprisingly high quantum efficiency. The long recombination lifetimes make it possible to observe not only the so-called bright exciton, but also its counterpart, the energetically lower lying dark exciton. First results will be presented, which explore the application of Silicon nanoparticles as a printable semiconductor material for optoelectronics.