Solute redistribution during the accelerated crucible rotation Bridgman growth of Hg_1-xMn_xTe

In order to study the Mn macrosegregation in accelerated crucible rotation Bridgman growth of Hg_1-xMn_xTe crystals, a 5 mm-diameter Hg_0.89Mn_0.11 Te ingot was grown by this method. It is shown that a single crystals is obtained in the early stage of the ingot after the competitive growth of several grains in the initial region. However, the single crystal is blocked by several new grains, which were nucleated on the ampoule wall after about 1 cm. The composition distribution along the growth direction was analyzed by electron probe. The results show that the Mn content in the initial region is relatively higher than the average value and then it reduces gradually to a very low value in the final region. Based on a quantitative analysis, several assumptions were made and a mathematical model was established for the evaluation of the solute (Mn) distribution in the growth direction. The calculation results obtained with this model are essentially coincident with the experimental data in the main part of the ingot growth. But the calculated Mn values are higher than the experimental data in the initial region and lower in the final region. These errors may stem from the approximation of homogeneous mixture in the liquid, which is not true in the initial and final regions because the convection there is limited.