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

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.