Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - CRYVISIL (Crystalline and vitreous silica films and their interconversion)

Teaser

Amorphous materials are omnipresent in our everyday life. The glass formation and the crystal-glass transition at the atomic level are still open fields in research. Clarifying the mechanisms at the atomic level during glass formation is crucial for a fundamental understanding...

Summary

Amorphous materials are omnipresent in our everyday life. The glass formation and the crystal-glass transition at the atomic level are still open fields in research. Clarifying the mechanisms at the atomic level during glass formation is crucial for a fundamental understanding of glasses and amorphous materials in general. In this project, surface science techniques are used for following dynamic processes in silica thin films. For this purpose, we are developing a high-speed scanning tunneling microscope (STM), which can access a wide temperature range. The work is implemented by other studies on existing experimental setups, such as low energy electron microscopy (LEEM) and spectroscopy (PEEM).

Work performed

In the first reporting period, experimental equipment was designed, installed and tested. We developed software for automated characterization of surface structures. Currently, we implement an automated device control system and new concepts of effective high speed scanning. This will guarantee high frame rates, which are required in order to monitor dynamic processes at the atomic scale in real space.
In parallel, we presented a new polymorph of the 2D silica film. This may allow for important insights into growth modes and transformations of 2D silica films as a model system for the study of glass transitions. In order to broaden the focus we also spent some time on further amorphous oxide film systems. We presented the growth and microscopic characterization of 2D germania films and obtained a comprehensive image of the germania film structure. In addition using the low energy electron microscopy (LEEM) and spectroscopy (PEEM) instrument, the temperature range for the glass formation and apparent activation energies have been explored.

Final results

The previous studies are the basis for monitoring dynamic processes at the atomic scale in oxide network structures as a function of temperature and time well beyond the state of the art.