Molecular dynamics simulations of silicon carbide nanowires under single-ion irradiation

Understanding irradiation effects is crucial for risk management in space science as well as technological development in material processing, imaging, and radiotherapy. The single-particle event is a stepping stone to this complicate, multiscale problem, which finds relevance in low-dose irradiation where long-term effects are usually concerned. Using molecular dynamics simulations, we explore the responses of crystalline silicon carbide nanowires under single-Ga-ion irradiation. It turns out that the channeling mode is more probable compared to focusing for crystalline surfaces at a normal angle of incidence. We find that the surface of nanowires plays a dual role as sites for both defect nucleation and annihilation, leading to notable diameter-dependent responses to the irradiation. The defects created in a single-ion event are localized within a few nanometers, and there exists a critical diameter for nanowires to be minimally damaged. These results allow quantitative assessment of the irradiation damage of nanostructures and guide their design for irradiation-resistant applications.