Direct and manage the Center for Silicon Photovoltaics – Lab for Crystallization Technologies at the Fraunhofer Institute in Halle. The focus of our work is the crystallization of silicon (Czochralski, Float Zone, and Directional Solidification), the development of new hardware, the characterization of material and the recycling and refinement of silicon. Our crystallization technology is based on state-of-the-art industrial-size equipment, our customers are major German companies for PV-products and PV-related machinery. Since 2013: appointed as professor at the Martin-Luther-University at Halle-Wittenberg.

Responsible for the development of a new technology for poly-silicon feedstock production. The new technology is based on a metallurgical pre-processing, followed by a chlorosilane based CVD process. The CVD reactors are independent production units, operating in a closed loop system. Chlorination and deposition takes place at the same time, the process gases are circulating between chlorination and deposition chamber. Further on, active as a guest scientist at the University of Waterloo (UW).

The activities were related to high resolution, in-situ analysis of nucleation and crystallization processes. Advanced characterization tools had been tested, used, and further improved. Key Achievements o Develop new theories with respect to stability of crystallization interfaces and the role of nucleation rates and step velocitieso Measure nucleation rates and step velocities on molecular levels using phase shift interferometryo Design and test new analytical tools for high resolution in-situ observation of nucleation and crystallization processes

Head of the research group “Elemental Semiconductors”, working with all major crystallization techniques for melt growth (Czochralski, Float Zone, Directional Solidification).Key Achievementso Establish the use of rotating and alternating magnetic fields for Czochralski and for Float Zone growth o In-situ observation of convectively driven temperature instabilities in silicon meltso Improve the heat and mass transport during Czochralski and FZ growth of silicon, germanium, and different III-V semiconductorso Ultrasound observation of solid-liquid interfaces during solidification of silicono Investigate material properties of silicon-germanium mixed crystalso Directing and heading a research group for numerical simulation o Give lectures in material sciences, crystal growth, and crystallography