25 August 2008 Sapphire fibers grown from the melt by the EFG technique: dependence of the impurity distribution on temperature and surface tension gradients
Author Affiliations +
Abstract
A stationary 2D axis-symmetric model able to evaluate the impurity distribution is developed by the finite element method for single-crystal sapphire fibers grown from the melt by the edge-defined film-fed growth (EFG) technique. The computations are carried out for two cases-one where the buoyancy is taken into account and the other where the buoyancy is neglected-using different vertical temperature gradients kg in the furnace. The dependence of the impurity distribution on kg and the Marangoni numbers Ma corresponding to the different surface tension gradients dγdT is analyzed. Computations reveal critical Marangoni numbers Mac determined by the fluid flow behavior, and that a smaller kg assures the best homogeneity of the crystal over a wide range of dγ/dT.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Thomas F. George, Thomas F. George, Liliana Braescu, Liliana Braescu, } "Sapphire fibers grown from the melt by the EFG technique: dependence of the impurity distribution on temperature and surface tension gradients", Proc. SPIE 7056, Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications II, 705603 (25 August 2008); doi: 10.1117/12.793279; https://doi.org/10.1117/12.793279
PROCEEDINGS
10 PAGES


SHARE
Back to Top