大尺寸TlBr单晶生长及其室温核辐射探测器的制备技术研究

溴化铊（TlBr）是一种非制冷型核辐射探测器用新型宽禁带化合物半导体材料，与GaAs、PbI2、CdZnTe等半导体探测材料相比，TlBr由于其物理特性优良且易于熔融生长等特点成为制备高能射线探测器的热点材料。本项目拟在设计、仿真并制作多温区精密控温晶体生长炉的基础上，利用垂直梯度凝固法生长大尺寸TlBr单晶，系统研究温度梯度、生长速率、安瓿直径等关键生长参数对大尺寸晶体的生长界面、晶体完整性及光学和电学性能的影响，以及研究晶体的气氛生长对晶体热缺陷的控制作用，结合各种表征手段来研究大尺寸TlBr晶体生长动力学机制及缺陷热力学，从而制备出结晶缺陷少、完整性好、光电特性优良的大尺寸TlBr单晶；在此基础上对探测器晶片的加工及表面处理工艺、电极材料类型及结构形式、晶片厚度、器件结构等进行系统研究，以获得稳定性好、探测效率高、能量分辨率优良的平面型及阵列型室温核辐射探测器。

TlBr is a novel wide band-gap compound semiconductor for room-temperature nuclear detectors. Compared to other compound semiconductors such as GaAs、PbI2 and CdZnTe, TlBr received more attention as a material for high energy radiation detection due to its excellent intrinsic properties and its easy growth from melt. Based on the design、simulation and fabrication of a multizone temperatue furnace with a precisely controlled temperature gradient by a plurality of heating elements, vertical gradient freezing method will be conducted to grow large volume TlBr crystals in this project. The influence of some key parameters, such as temperature gradient, growth rate, and ampoule diameter on the shape of solid-liquid boundary, crystal perfection, and electrical and optical characteristics of the obtained crystals will be systematically studied. In addition, various ambient will be conducted to control defects in the crystals. To understand the mechanism of the crystal growth and to obtain good-performance TlBr crystals with less defects, good perfection, and good electrical and optical characteristics, the dynamics of crystal growth and thermodynamics of defects will be investigated through various characterization. Furthermore, in order to produce high-performance TlBr detectors, several processing-related factors will be considered in detail, such as the method and quality of cutting, polishing and etching, the type and the configuration of electrodes, the size of the wafers and the configuration of detectors. The aim of this research is to obtain planer and pixelled room-temperature detectors with good time stability, good energy resolution and high detection efficiency.