Molecular dynamics simulation of the effects of swift heavy ion irradiation on multilayer graphene and diamond-like carbon

• Published in: Applied surface science 2020-10, Vol.527, p.146495, Article 146495
• Main Authors: Liu, Jian, Vázquez Muíños, Henrique, Nordlund, Kai, Djurabekova, Flyura
• Format: Article
• Language: English
• Subjects: Diamond-like carbon; Inelastic thermal spike model; Molecular dynamics; Multilayer graphene
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.146495

[Display omitted] •A DLC-protected multilayer graphene on diamond is irradiated by 91 MeV Xe23+ ions.•Swift heavy ion impact is simulated by molecular dynamics and two-temperature model.•Analysis shows structural changes and drop in number of sp3 bonds in tracks in DLC.•Ring analysis shows remaining chaotic structure in tracks even after long relaxation. As a promising material used in accelerators and in space in the future, it is important to study the property and structural changes of graphene and diamond-like carbon on the surface as a protective layer before and after swift heavy ion irradiation, although this layer could have a loose structure due to the intrinsic sp2 surrounding environment of graphene during its deposition period. In this study, by utilizing inelastic thermal spike model and molecular dynamics, we simulated swift heavy ion irradiation and examined the track radius in the vertical direction, as well as temperature, density, and sp3 fraction distribution along the radius from the irradiation center at different time after irradiation. The temperature in the irradiation center can reach over 11000 K at the beginning of irradiation while there would be a low density and sp3 fraction area left in the central region after 100 ps. Ring analysis also demonstrated a more chaotic cylindrical region in the center after irradiation. After comprehensive consideration, diamond-like carbon deposited by 70 eV carbon bombardment provided the best protection.