ZnTe晶体因其优异的电光性能，而被成功用于脉冲太赫兹成像。但由于晶体缺陷制约了太赫兹成像的灵敏度和分辨率，而单晶尺寸小则限制了成像的空间采样率。本项目拟采用碲熔剂温度梯度溶液法生长直径60mm的ZnTe基晶体，通过对结构缺陷和物理性能的表征，探索影响其太赫兹成像质量的关键因素。主要研究：(1)掌握碲溶液法制备ZnTe晶体的理论和技术，揭示ACRT参数和梯度变化温场对液/固界面形状和成分均匀性的影响。(2)构建多缺陷耦合作用及相互转化的模型，发展元素掺杂和后续晶片退火方法，实现对晶体中微米级富Te相和Zn空位等电活性缺陷的调控。(3)建立ZnTe晶体物理性能与THz场波前信息的关系，归纳影响太赫兹成像分辨率、信噪比和均匀性的主要因素。通过优化晶体生长工艺以及开展多阶段组合晶片退火，获得满足成像应用要求的大尺寸高光学品质ZnTe单晶，为推动我国太赫兹成像设备和技术的发展奠定理论和技术基础。

ZnTe crystals have emerged as one of the mostly used electro-optic materials for pulsed terahertz (THz) imaging. However, the as-grown ZnTe single crystals with plenty of microstructure defects have degraded the sensitivity and resolution. The limited wafer size restricts the spatial sampling rate, which hampered the adoption of the state of art THz imaging devices. In this project, temperature gradient solution method will be employed combined with the ACRT technique to grow ZnTe crystals with dimension of 60 mm. Meanwhile, the structure defects behaviors and its physical properties will be investigated. The key parameters which determine the THz imaging quality will be explored. The main research proposals are as follows: (1) To achieve the theory and technique for ZnTe crystal growth based on the Te-solvent method. The morphology of liquid/solid interface and the composition uniformity associated with the ACRT parameters and gradient temperature field are evaluated. (2) The coupling effects of multi-defects on ZnTe physical properties are proposed. The intentional doping and post-growth annealing are developed. In turn, the micro-scale Te-rich particles and Zn vacancy associated isoelectric active defects are tailored. (3) The correlation between ZnTe properties and the resulting THz field information is discussed. The key factors which influence the resolution, signal-to-noise ratio and uniformity of the THz imaging based on ZnTe crystals are concluded. Finally, the large size ZnTe-based crystals with superior electro-optic properties will be obtained by optimizing the crystal growth processing and the multi-steps wafer annealing, in turn, to promote the development of THz imaging equipment and the corresponding technology in China.