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Solarzellen werden oft aus multikristallinem Solar-Silizium hergestellt. Dessen Züchtung aus der Schmelze trägt zu den Kosten des gebrauchsfertigen Solarmoduls bei. Das Ziel moderner Kristallzuchtverfahren ist die Senkung dieser Kosten bei gleichzeitiger Erhöhung der Kristallqualität.

Ausführlichere Darstellungen der WIAS-Forschungsthemen finden sich auf der jeweils zugehörigen englischen Seite.

Publikationen

  Artikel in Referierten Journalen

  • P.-É. Druet, Some mathematical problems related to the second order optimal shape of a crystallization interface, Discrete and Continuous Dynamical Systems, 35 (2015), pp. 2443--2463.
    Abstract
    We consider the problem to optimize the stationary temperature distribution and the equilibrium shape of the solid-liquid interface in a two-phase system subject to a temperature gradient. The interface satisfies the minimization principle of the free energy, while the temperature is solving the heat equation with a radiation boundary conditions at the outer wall. Under the condition that the temperature gradient is uniformly negative in the direction of crystallization, the interface is expected to have a global graph representation. We reformulate this condition as a pointwise constraint on the gradient of the state, and we derive the first order optimality system for a class of objective functionals that account for the second surface derivatives, and for the surface temperature gradient.

  • CH. Kudla, A.T. Blumenau, F. Büllesfeld, N. Dropka, Ch. Frank-Rotsch, F. Kiessling, O. Klein, P. Lange, W. Miller, U. Rehse, U. Sahr, M. Schellhorn, G. Weidemann, M. Ziem, G. Bethin, R. Fornari, M. Müller, J. Sprekels, V. Trautmann, P. Rudolph, Crystallization of 640 kg mc-silicon ingots under traveling magnetic field by using a heater-magnet module, Journal of Crystal Growth, 365 (2013), pp. 54--58.

  Beiträge zu Sammelwerken

  • N. Dropka, W. Miller, U. Rehse, P. Rudolph, F. Bullesfeld, U. Sahr, O. Klein, D. Reinhardt, Numerical study on improved mixing in silicon melts by double-frequency TMF, in: Proceedings of the 16th International Conference on Crystal Growth (ICCG-16), J. Crystal Growth, 318, 2011, pp. 275--279.

  Vorträge, Poster

  • O. Klein, Modeling and numerical simulation of the application of traveling magneticfields to stabilize crystal growth from the melt, 12th International Conference on Free Boundary Problems: Theory and Applications, June 11 - 15, 2012, Frauenchiemsee, June 11, 2012.

  • W. Dreyer, P.-É. Druet, F. Duderstadt, Ch. Grützmacher, O. Klein, D. Reinhardt, J. Sprekels, Ch. Frank-Rotsch, F.-M. Kiessling, W. Miller, U. Rehse, P. Rudolph, Ch. Lechner, Crystal growth under the influence of traveling magnetic fields, Status Seminar AVANTem SOLAR, Griebnitzsee, September 9 - 10, 2010.

  • O. Klein, K. Afanasiev, F. Duderstadt, W. Dreyer, S. Eichler, J. Sprekels, On effects in the vicinity of the solid melt interface during crystal growth from the melt, The 16th International Conference on Crystal Growth (ICCG-16) in conjunction with The 14th International Conference on Vapor Growth and Epitaxy (ICVGE-14), Beijing, China, August 8 - 13, 2010.

  • O. Klein, Modeling and simulations for directional solidification of solar-grade silicon under the influence of traveling magnetic fields, The 16th International Conference on Crystal Growth (ICCG-16) in conjunction with The 14th International Conference on Vapor Growth and Epitaxy( ICVGE-14), August 8 - 13, 2010, Beijing, China, August 10, 2010.

  • O. Klein, Numerical simulation of the use of traveling magnetic fields to stabilize crystal growth from the melt, Warsaw Seminar on Industrial Mathematics (WSIM'10), March 18 - 19, 2010, Warsaw University of Technology, Poland, March 18, 2010.