Mathematical Model for the Simulation of Crystallization of CdTe in a vertical Bridgman Furnace.

ABSTRACTTemperature measurements in a crystal growth ampoule of CdTe (Cadmium Telluride) are very difficult. Mathematical simulation is a very powerful tool to predict the behavior and temperature distribution during crystal growth. We applied this technique to the bulk growth of large single crystals of CdTe. The simulation revealed that for CdTe, it is possible to create a convex interface shape during growth, necessary for single crystal growth. The controlling parameter is the temperature profile along the ampoule. The temperature gradient is rather meaningless, as we can show with our simulations.We will present some crystals grown under good and bad thermal conditions.

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The plane-to-cellular-to-dendrite transition of the shape of the crystallization front during the crystallization of Al-Cu alloys

Journal of the Serbian Chemical Society ◽

10.2298/jsc0603303r ◽

2006 ◽

Vol 71 (3) ◽

pp. 303-312

Author(s):

Vesna Radojevic ◽

Andreja Valcic ◽

Slobodanka Nikolic ◽

Aleksandar Golubovic

Keyword(s):

Heat Transfer ◽

Mathematical Model ◽

Finite Element Method ◽

Finite Element ◽

Crystal Growth ◽

Temperature Gradient ◽

Crystallization Front ◽

The Finite Element Method ◽

Cu Alloys ◽

Vertical Bridgman

The evolution of the crystallization front from a planar to a dendritic one as a function of the G L/(Rc 0) parameter was investigated during the crystallization of Al-Cu alloys by the vertical Bridgman method. Six series of alloys with different initial compositions of Cu were solidified at different growth rates. A mathematical model for the heat transfer during vertical Bridgmen crystal growth was developed. The model was solved using the finite element method. The temperature gradient in the melt at the beginning of crystal growth was calculated using the obtained model. Discrete stages of the crystallization front were identified in the experiments, as the ratio G L/(Rc 0) decreased.

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Effect of Marangoni Convection on InSb Single Crystal Growth by Horizontal Bridgman Method

MRS Proceedings ◽

10.1557/proc-692-h8.6.1 ◽

2001 ◽

Vol 692 ◽

Author(s):

K. Kodera ◽

A. Kinoshita ◽

K. Arafune ◽

Y. Nakae ◽

A. Hirata

Keyword(s):

Crystal Growth ◽

Binary System ◽

Temperature Gradient ◽

Single Crystal ◽

Grown Crystal ◽

Marangoni Convection ◽

Single Crystal Growth ◽

Control Technique ◽

Growth System

AbstractIt is necessary to clarify the effect of Marangoni convection on single crystal growth from a melt in order to improve the quality of the grown crystal. Particularly, the deviation of crystalmelt (C-M) interface from a planar shape is a major problem because it may deteriorate the quality of the grown crystal. In this paper, we investigated the effect of thermal and solutal Marangoni convection on C-M interface shape in an In-Sb binary system by the horizontal Bridgman (HB) method. The C-M interface concavity strongly depends on the cooling rate and the temperature gradient under uniform concentration distribution conditions in the melt. A large concavity was observed at low cooling rates and high temperature gradient conditions. The concavity was found to be caused by thermal Marangoni convection, by taking Péclet number into account. Then, we varied the composition of the In-Sb binary system to induce solutal Marangoni convection intentionally. The C-M interface was kept planar in case solutal Marangoni convection occurred in the direction opposite to the thermal one. Therefore, we believe that the utilization of solutal Marangoni convection will be a new control technique to make the C-M interface planar for the HB system. From these results, it was clarified that Marangoni convection plays a significant role in the HB crystal growth system.

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