Two-dimensional materials under ion irradiation: from defect production to structure and property engineering

Similar to their bulk 3D counterparts, the properties of two-dimensional (2D) materials can be tuned by controllable introduction of impurities and defects using beams of energetic ions, which requires complete microscopic understanding of their response to ion irradiation. The behavior of 2D materials under ion beam is also interesting in the context of their applications in radiation-hostile environments such as cosmic space. While irradiation effects in 3D systems are well understood, a growing body of experimental facts indicate that many concepts of energetic particle-solid interaction developed for 3D materials are not applicable to 2D systems due to their very geometry, or require substantial modifications. In this Chapter, we discuss at length the response of 2D materials to ion irradiation in different regimes with the main focus on the role of reduced dimensionality. We illustrate the differences between the impact of ions on 3D and 2D materials by examples taken from the recent theoretical and experimental studies on the response of 2D materials to ion irradiation and outline general trends in their behavior under irradiation. Finally, we discuss how ion beams can be used to engineer the structure and properties of 2D materials.