Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 44: Topical Session: TEM-Symposium - In-Situ II
MM 44.1: Vortrag
Mittwoch, 13. März 2013, 16:30–16:45, H25
Nanoscale investigation of metal-induced crystallization (MIC) and related mass transport by in-situ TEM/STEM — Balaji Birajdar1, Simon Kraschawski1, Benjamin Butz1, Tobias Antesberger2, Martin Stutzmann2, and •Erdmann Spiecker1 — 1Center for Nanoanalysis and Electron Microscopy (CENEM), Department Werkstoffwissenschaft, Universität Erlangen-Nürnberg — 2Walter Schottky Institut and Physics Department, Technische Universität München
The MIC process enables fabrication of thin polycrystalline Si films at relatively low temperature (< 450°C) making it highly promising for thin film photovoltaics. The microscopic mechanism of materials transport during the layer exchange is still largely unknown. Here the microstructure of a-Si/metal/Quartz stacks, in-situ annealed at 450-530 °C, have been investigated at different length scales by combining optical microscopy and analytical TEM/STEM [1]. In particular Ag metal layer was used to directly visualize the material transport by Z-contrast imaging in STEM due to the large difference in atomic numbers of Ag and Si. Like in Al induced crystallization, Si grains are nucleated in the original Ag layer and grow dendritically as the smaller Ag grains were preferentially replaced by Si. The replaced Ag was observed to concentrate over the larger Ag grains replacing the a-Si which appears to diffuse out. Thus in contrast to Al induced crystallization a continuous Si film could not be formed, indicating the importance of Ag grain size distribution. [1] B. Birajdar, T. Antesberger, M. Stutzmann, E. Spiecker, Scripta Mater. 66, 550 (2012).