  Using atomistic computer simulations, we study how ion irradiation can be
used to alter the morphology of a graphene monolayer by introducing defects of
specific type, and to cut graphene sheets. Based on the results of our
analytical potential molecular dynamics simulations, a kinetic Monte Carlo code
is developed for modelling morphological changes in a graphene monolayer under
irradiation at macroscopic time scales. Impacts of He, Ne, Ar, Kr, Xe and Ga
ions with kinetic energies ranging from tens of eV to 10 MeV and angles of
incidence between 0\circ and 88\circ are studied. Our results provide
microscopic insights into the response of graphene to ion irradiation and can
directly be used for the optimization of graphene cutting and patterning with
focused ion beams.
