碲锌镉晶体合成过程中的放热控制和反应机理研究

Study on Controllable Heat Release and Reaction Mechanism During Synthesis of CdZnTe Crystal

碲锌镉(Cadmium Zinc Telluride,CZT)是碲镉汞(Mercury Cadmium Telluride,MCT)红外焦平面器件的重要衬底材料,其合成过程存在强烈的放热现象。因此控制放热是CZT多晶材料合成工艺平稳进行的基本条件。通过改变初始旋转倾角可有效调控合成反应的放热强度和放热速率:大倾角有利于获得缓慢且稳定的工艺过程。基于实验结果和热力学计算分析可知,合成反应经过镉--碲的液--固相反应和液--液相反应两个阶段完成。同时实验结果表明,反应的放热量大小决定了在高温下是否会发生第二次反应。最后对二次反应发生的相关机理进行了分析。

Cadmium zinc telluride(CZT)is an important substrate material for mercury cadmium telluride(MCT)infrared focal plane array devices.There is a strong exothermic phenomenon during the synthesis of CZT polycrystal.Therefore,controlling the heat release is the basic condition for the smooth progress of the CZT polycrystal material synthesis process.The exothermic intensity and rate of the synthesis reaction can be effectively controlled by changing the initial tilt angle,and a large tilt angle is beneficial to obtain a slow and stable process.Based on the experimental results and thermodynamic analysis,it is shown that the synthesis reaction can be divided into two stages,including liquid-solid phase reaction and liquid-liquid phase reaction between Cd and Te.Meanwhile,the experimental results show that the amount of heat released from the synthesis reaction determines whether the second reaction will occur at high temperatures.Finally,the related mechanism of the secondary reaction is analyzed.