Forschergruppe FOR 759

The Formation of Planets:
The Critical First Growth Phase

Project A1

EXPERIMENTAL SETUP

We have embarked on a new strategy by using amorphous thin films deposited on a silicon-wafer via PLD (Pulsed Laser Deposition). The thickness of the wafer is 350µm coated with a PLD thin film in the order of about 200 nm. Thin films usually have a thickness in the range of some 100 nm up to 1µm.

With this method we obtain a chemically well-defined amorphous thin film of stoichiometric composition with a constant and accurate adjustable thickness (Dohmen et al. 2002).

We have developed a simple annealing sequence in a vertical quench furnace. Before and after annealing, the sample is characterized not only by IR spectroscopy but also by AFM (Atomic Force Microscopy), SEM (Scanning Electron Microscopy), XRD (x-ray powder diffraction) and TEM (Transmission Electron Microscopy).We combine multiple methods for the characterization of the samples in order to improve the definition of the degree of crystallinity and eventually to relate the experimental results to astronomical data.

For comparison we also intend to use gels as starting materials.