垂直布里奇曼法CdMnTe晶体生长过程的数值模拟与实验研究

为经济高效获得Cd_1-xMn_xTe晶体垂直布里奇曼法(vertical Bridgman method,VBM)生长条件，基于有限元软件建立二维有限体积数值模型，模拟了VBM生长Cd_1-xMn_xTe的晶体过程；探究坩埚内部熔体的传热、流动以及生长界面变化情况，分析5、10和15 K/cm 3种不同温度梯度条件对固液界面的影响。结果表明，晶体生长初期，固液界面径向流速差较大，从而使生长界面略凹向晶体；随着晶体生长的进行，固液界面逐渐平缓，开始有利于良好晶体的生长；在生长中后期，固液界面变为凸面，随着温度梯度的增大，可以更好地抑制对流，有利于获得高质量晶体。在模拟结果的基础上，调整不同阶段坩埚下降速度，进行Cd_0.9Mn_0.1Te晶体的制备，成功地生长出质量良好的Cd_0.9Mn_0.1Te晶体。

Numerical Simulation and Experimental Study on the Growth Process of CdMnTe Crystal by Vertical Bridgman Method

The growth process of Cd0.9Mn0.1Te crystal by vertical Bridgman method (VBM) was simulated in detail by Fluent software. A two-dimensional finite volume numerical model was established to discuss the heat transfer, flow and growth interface of the melt in the crucible. The effects of three different temperature gradient conditions (5 K / cm, 10 K / cm and 15 K / cm) on the solid-liquid interface were analyzed. The results show that under the model calculation conditions, with the increase of temperature gradient, the trend of interface concave to liquid region increases in the middle growth period, which can better suppress convection. With the crystal growth, the melt ratio will continue to decrease, the melt flow rate near the growth interface increases gradually, and the flow velocity fluctuation increases gradually. The experimental conditions were improved according to the simulation results, and CdMnTe crystals with good quality were finally grown.