Effect of heat shield on the shape of the solid–liquid interface and temperature field in the BGO-eulithine LTG Cz growth

Abstract

In an effort to eliminate the strong deflection of the solid–liquid interface (SLI) toward a melt, caused by specular (Fresnel) reflection of heat radiation at the crystal surface, we have performed an experimental and numerical study of the growth of Bi 4Ge 3O 12 crystals in the presence of a thermal shield located directly above the crystal shoulder. A platinum shield of a conic shape was used in experiment, while in simulation the shape and radiative properties of the shield are varied. Both experiment and simulation showed that although the shield appreciably decreases the deflection of the solid–liquid interface, increases the size of the facets and diminishes the density of gas inclusions at the initial stage of the growth, the cardinal decrease of the deflection of the interface did not happen.