勾形磁场对分离结晶法制备CdZnTe晶体的影响

Effect of Cusp Magnetic Field on CdZnTe Crystal Growth by Detached Solidification

为了了解勾形磁场对CdZnTe晶体生长质量的影响,利用有限元法对坩埚内的热量和动量传递过程进行了全局数值模拟。假定熔体和气相中的流动都为准稳态轴对称层流,研究了B_o(磁场轴线与晶体-坩埚界面的交点的磁场强度的轴向分量)为0 T,0.5 T,1.0 T,1.5 T,2.0 T,2.5 T,3.0 T时的CdZnTe晶体生长过程。结果表明:勾形磁场能有效抑制熔体内的流动,会产生由洛仑兹力、表面张力和浮力共同驱动的涡胞。随着磁场强度的增加,传热向导热型转变,熔体内最大流函数逐渐减小,抑制作用增强。

In order to understand the effect of cusp magnetic field on the growth quality of CdZnTe crystal,a set of global analyses for heat and momentum transfers in crucible was carried out using the finite-element method.It was assumed that the flow was axisymmetric stable laminar in both the melt and the gas.We researched the growth of CdZnTe crystal when the intensity of magnetic field is equal to OT,0.5 T,1.0 T,1.5 T,2.0 T,2.5 T and 3.0 T,respectively.The results show that the melt flow was suppressed by the cusp magnetic field and the toroidal roll cells which driven by Lorentz, Marangoni and buoyancy were found in the melt.The increase in magnetic field strength causes the heat transfer convert into the heat conduction and consequently leads to reduce in the maximum stream function,and increase in the inhibition.