State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
Department of Engineering Physics Ministry of Education Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Beijing, 100084, P. R. China.
Adv Mater. 2023 Jun;35(24):e2212213. doi: 10.1002/adma.202212213. Epub 2023 Apr 27.
Direct neutron detection based on semiconductor crystals holds promise to transform current neutron detector technologies and further boosts their widespread applications. It is, however, long impeded by the dearth of suitable materials in the form of sizeable bulk crystals. Here, high-quality centimeter-sized LiInP Se single crystals are developed using the Bridgman method and their structure and property characteristics are systematically investigated. The prototype detectors fabricated from the crystals demonstrate an energy resolution of 53.7% in response to α-particles generated from an Am source and robust, well-defined response spectra to thermal neutrons that exhibit no polarization or degradation effects under prolonged neutron/γ-ray irradiation. The primary mechanisms of Se-vacancy and In antisite defects in the carrier trapping process are also identified. Such insights are critical for further enhancing the energy resolution of LiInP Se bulk crystals toward the intrinsic level (≈8.6% as indicated by the chemical vapor transport-grown thin crystals). These results pave the way for practically adopting LiInP Se single crystals in new-generation solid-state neutron detectors.
基于半导体晶体的直接中子探测有望改变当前的中子探测器技术，并进一步推动其广泛应用。然而，由于缺乏合适的材料（大尺寸块状晶体），这一目标一直难以实现。在这里，使用布里奇曼法开发出了高质量的厘米级 LiInP Se 单晶，并对其结构和性能特征进行了系统研究。由这些晶体制造的原型探测器对来自 Am 源的 α 粒子的响应表现出 53.7%的能量分辨率，并且对热中子表现出稳健、清晰的响应谱，在长时间的中子/γ 射线辐照下没有极化或退化效应。在载流子俘获过程中，Se 空位和 In 反位缺陷的主要机制也被确定。这些见解对于进一步提高 LiInP Se 体单晶的能量分辨率以达到本征水平（由化学气相输运生长的薄晶体指示为≈8.6%）至关重要。这些结果为在新一代固态中子探测器中实际采用 LiInP Se 单晶铺平了道路。
