ZnO基超快闪烁晶体慢光发射特性研究

ZnO-based ultrafast scintillation crystal is one of the fastest inorganic scintillators discovered so far that has potential applications in the investigations for ultrafast phenomena in the field of laser fusion and nuclear physics. However, the scintillation property of ZnO-based crystal is adversely affected by slow components of transient photoluminescence caused by unintentional impurities and point defects. So far, the induced mechanism is still not well understood. In this program, we plan to introduce impurities and point defects of different types into ZnO high-pure crystals through vapor diffusion, and then investigate transient photoluminescence emissions of obtained crystals induced by high-power ultraviolet subpicosecond laser. The high time-resolved streak camera is used to study the photoluminescence spectrum. Based on these measurements, we plan to study the corresponding relationship between slow components and introduced defects, the relationship between slow components and fast components, as well as the origin of slow components. Through this program, the mechanism of slow photoluminescence emissions of ZnO-based crystals should be revealed. A reasonable slow emissions control method may hopefully be established. The results should provide the scientific basis for developing new scintillation detection methods for ultrafast phenomena under extreme conditions.

ZnO基超快闪烁晶体是迄今发现具有最快时间响应的无机闪烁体之一，有望应用于激光聚变和核物理研究中对超快过程的探测。但是，ZnO基晶体中非故意引入杂质和点缺陷引起的瞬态发光慢成分较多，影响了晶体闪烁性能；慢光发射的产生机制目前仍不明确。为此，本项目拟采用气相扩散在高纯ZnO晶体中人为引入不同类型的杂质和缺陷，采用高功率亚ps超短脉冲激光激发改性晶体，采用高时间分辨条纹相机将瞬态发光谱在时间维度展开。在此基础上，研究慢光起源和演化机理，研究慢光与缺陷状态关系，研究快、慢光互相影响机制。本项目旨在揭示ZnO基超快闪烁晶体慢光发射的物理机制，建立慢光产额抑制方法，为发展新型超快闪烁探测技术提供科学依据。

ZnO基超快闪烁晶体是迄今发现具有最快时间响应的无机闪烁体之一。ZnO基晶体中非故意引入杂质和点缺陷引起的发光慢成分较多，对晶体性能造成影响。本项目围绕ZnO基晶体缺陷状态、瞬态发光以及慢光发射性质等开展研究。获得了慢成分绿光GL起源、GL峰蓝移及精细结构与Zni缺陷，Vo缺陷以及Vzn缺陷的关系。明确了晶体快、慢发光成分均受到本征缺陷影响，揭示了ZnO晶体内应力、缺陷状态与晶体性质的关系，提出了以退火和气相掺杂等方法提高ZnO基晶体的发光性能，为发展新型超快闪烁探测技术提供了依据。