Directional solidification and cha5racterization of Hg_0.89Mn_0.11Te

摘要

Two boules of Hg_0.89Mn_0.11Te (MMT) were solidified by thekl vertical Bridgman-Stockbarger method using translation rates of 0.09 and 0.18 μm/s. The influence of grwoth rate on axial compositional homogeneity in the MMT oulesd was evaluated experimentally through precision density measruements on radial slices from each boule. In addtion, planek front solidificagtion theory and segregaion coefficient (k) data fro the Hg_1-xMn_x system were used to fitk theoretical compostion profiles to the measrued MMT axial compostion profiles. The strong correlation between the measured and calcualted MMT axial composition profiles indicated diffusion dominated axial solute redistribution in the boules under the applied growth conditions. The analysis of the MMT axial composition profiles allowed the calculation of the effective diffusion coefficient (D_eff=3.75×10~-5 cm~2/s) for MnTe in molten MMT. The k-values for the Hg_1-xMn_xTe system and the D_eff were used to show that both boules were solidifiekd under conditions which did not exceed the constitutional supercooling criteria under ideal conditions. Finally, an initial compariosn of the radial exceed the constitutional supercooling criteria under ideal conditions. Finally, an initial compariosn of the radial compositional variations in each boule, as determiend by a Fourier transofrk infra-red spectroscopy (FTIR) technique, was made.