Investigation of the Radiation Damage Mechanisms in Two-Dimensional Materials under Gamma and Ion Irradiation

该项目将重点研究二维过渡金属二硫族化合物（TMDCs）、六方氮化硼（h-BN）和石墨烯的合成和辐照后表征，以阐明这些材料的辐射损伤机制。2D材料杰出的电子和光电子特性证明了这项研究的重要性，这使得这类化合物成为各种电子设备（包括辐射剂量计和探测器）应用的良好候选者。虽然石墨烯对电离辐射具有极高的抵抗力，但与石墨烯二维无机化合物（如h-BN、MoS2和WS2）结构相关的辐射硬度尚未得到系统研究。由于无机二维材料具有更复杂的层状结构和多元素化学组成，预计其辐射损伤将与石墨烯大不相同。据我们所知，文献中只有少数关于二维材料的辐照研究。这些研究大多依赖于透射电子显微镜作为一种工具，用于高能电子的原位辐射损伤和同时观察缺陷。这种实验方法提供了有关电子辐照下缺陷形成机制的宝贵信息。然而，它并不代表在高能加速器和对撞机、放射治疗设施或核反应堆中发现的恶劣辐射条件。在这些环境中，含有无机二维材料的电子器件将暴露在高能、高剂量的混合辐射场中。我们建议伽马和离子照射可以用来模拟这些条件。将在道尔顿坎布里亚设施（DCF）部署Co60辐照器和5MV双列离子加速器，分别通过伽马射线和重离子轰击产生晶格损伤样品。使用拉曼光谱、傅里叶变换红外光谱、原子力显微镜、扫描电子显微镜和透射电子显微镜检查所研究的二维材料的辐射分解变化。提出的辐照二维材料的广泛表征将允许量化晶格损伤的程度，并更好地理解辐射诱导降解的机制。所提出的研究将对无机二维材料和石墨烯的辐射硬度（或不稳定性）的基本理解做出重要贡献。

The project will be focused on the synthesis and post-irradiation characterisation of a number of 2D transition metal dichalcogenides (TMDCs), hexagonal boron nitride (h-BN) and graphene in order to elucidate the radiation damage mechanisms in these materials. The importance of the proposed study is justified by the outstanding electronic and optoelectronic properties of 2D materials, which make this class of compounds a good candidate for applications in various electronic devices, including radiation dosimeters and detectors. While exceptionally high resistance of graphene against ionising radiation is well recognised, the radiation hardness of the structurally related to graphene 2D inorganic compounds (such as h-BN, MoS2, and WS2) haven't been studied systematically. It is expected that the radiation damage in inorganic 2D materials will be quite different from graphene due to more complex layered structure and multi-element chemical composition of these compounds. To the best of our knowledge, there are just a few irradiation studies of 2D materials that can be found in literature. Majority of these investigations relies on the transmission electron microscopy as a tool for in situ radiation damage by energetic electrons and simultaneous defect observation. This experimental approach yields valuable information about the mechanisms of defect formation under electron irradiation. However, it does not represent harsh radiation conditions found in high-energy accelerators and colliders, radiotherapy facilities or nuclear reactors. In these environments, electronic devices containing inorganic 2D materials will be exposed to the high energy and high dose mixed radiation fields. We suggest that gamma and ion irradiation can be used to mimic those conditions. The Co60 irradiator and the 5MV tandem ion accelerator at the Dalton Cumbrian Facility (DCF) will be deployed to produce lattice damaged specimen by gamma rays and by heavy ion bombardment, respectively. Radiolytic changes in the studied 2D materials will be examined using Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Transmission Electron Microscopy. Proposed extensive characterisation of irradiated two-dimensional materials will allow to quantify the extent of lattice damage and to gain a better understanding of the mechanisms of radiation-induced degradation. The proposed studies will make an important contribution to the fundamental understanding of radiation hardness (or instability) of the inorganic 2D materials and graphene.