Solute redistribution during the accelerated crucible rotation Bridgman growth of Hg1-xMnxTe

In order to study the Mn macrosegregation in accelerated crucible rotation Bridgman growth of Hg1-xMnxTe crystals, a 5 mm-diameter Hg0.89Mn0.11Te ingo t was grown by this method. It is shown that a single crystal is obtained i n the early stage of the ingot after the competitive growth of several grai ns 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 electr on probe. The results show that the Mn content in the initial region is rel atively higher than the average value and then it reduces gradually to a ve ry low value in the final region. Based on a quantitative analysis, several assumptions were made and a mathematical model was established for the eva luation of the solute (Mn) distribution in the growth direction. The calcul ation 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 l ower in the final region. These errors may stem from the approximation of h omogeneous mixture in the liquid, which is not true in the initial and fina l regions because the convection there is limited. (C) 1999 Elsevier Scienc e B.V. All rights reserved.