Thermosolutal Convection and Solute Segregation of Hg_1−xCd_xTe Alloy During the Vertical Bridgman Single Crystal Growth

The thermosolutal convection and solute segregation of Hg_1-xCd_xTe alloy during the vertical Bridgman single crystal growth have been numerically analyzed. Based on the thermal properties changed with the temperature and concentration, the coupling laws between temperature and solute gradients in the melt and the effects of thermosolutal convection on the solute segregation are studied in the paper. The main results obtained are as followed. Firstly, the stabilizing solute gradient will damp the convection caused by temperature gradient in the melt. But the damping effect of solute gradient will be significant only when the absolute value of the solute Rayleigh Number increases to the thermal Rayleigh Number. Secondly, when the solute gradient is large, the upper flow in the melt will be a sideway diffusive instability flow and evolve to a twocell construction. Thirdly, the solute distribution in the melt is mainly determined by the flow intensity and construction and the solute segregation near the solidification interface will be improved as the intensity of the lower flow decreases.