title: Atomistic-Scale Simulations of Defect Formation in Graphene under Noble Gas Ion Irradiation.
abstract: Despite the frequent use of noble gas ion irradiation of graphene, the atomistic-scale details, including the effects of dose, energy, and ion bombardment species on defect formation, and the associated dynamic processes involved in the irradiations and subsequent relaxation have not yet been thoroughly studied. Here, we simulated the irradiation of graphene with noble gas ions and the subsequent effects of annealing. Lattice defects, including nanopores, were generated after the annealing of the irradiated graphene, which was the result of structural relaxation that allowed the vacancy-type defects to coalesce into a larger defect. Larger nanopores were generated by irradiation with a series of heavier noble gas ions, due to a larger collision cross section that led to more detrimental effects in the graphene, and by a higher ion dose that increased the chance of displacing the carbon atoms from graphene. Overall trends in the evolution of defects with respect to a dose, as well as the defect characteristics, were in good agreement with experimental results. Additionally, the statistics in the defect types generated by different irradiating ions suggested that the most frequently observed defect types were Stone-Thrower-Wales (STW) defects for He(+) irradiation and monovacancy (MV) defects for all other ion irradiations.
authors.affiliation: Department of Mechanical and Nuclear Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Kichul
authors.initials: K
authors.lastname: Yoon
authors.affiliation: Department of Mechanical and Nuclear Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Ali
authors.initials: A
authors.lastname: Rahnamoun
authors.affiliation: Advanced Technology Center, Lockheed Martin Space Systems Company , Palo Alto, California 94304, United States.
authors.forename: Jacob L
authors.initials: JL
authors.lastname: Swett
authors.affiliation: Department of Materials Science and Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Vighter
authors.initials: V
authors.lastname: Iberi
authors.forename: David A
authors.initials: DA
authors.lastname: Cullen
authors.forename: Ivan V
authors.initials: IV
authors.lastname: Vlassiouk
authors.forename: Alex
authors.initials: A
authors.lastname: Belianinov
authors.forename: Stephen
authors.initials: S
authors.lastname: Jesse
authors.forename: Xiahan
authors.initials: X
authors.lastname: Sang
authors.forename: Olga S
authors.initials: OS
authors.lastname: Ovchinnikova
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Rondinone
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Unocic
authors.affiliation: Department of Mechanical and Nuclear Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: Adri C T
authors.initials: AC
authors.lastname: van Duin
keywords: ReaxFF; aberration-corrected STEM; atomistic analysis of graphene; graphene defects; ion irradiation