On the nano-hillock formation induced by slow highly charged ions on insulator surfaces

Modelling surface restructuring by slow highly charged ions

“…The multi-scale model for the energy deposition by slow highly charged ions on a CaF 2 target is based on the scenario in which the initial deposition into the electronic degree of freedom and subsequently into the lattice degree of freedom proceeds on shorter time scales than the subsequent atomic rearrangements and structural changes [5,[9][10][11]. This allows to treat such processes separately.…”

“…As the slow highly charged ion approaches the surface, the primary energy conversion from potential energy of the projectile to electronic energy of the target proceeds by a complex de-excitation cascade, both above and below the surface [11][12][13][14][15]. As the ion approaches the surface, electron capture to highly excited projectile states sets in, followed by a subsequent de-excitation by Auger decay processes and radiative decay.…”

“…As a consequence, a large fraction of projectiles are still highly charged upon entering the first few of the interaction can be simulated using the classical-over-the-barrier model [12] and its extension to insulator surfaces [13]. A quantitative analysis of slow highly charged ion impact on CaF 2 is given in [11], relating the charge state of the projectile to the electron emission spectrum around the impact area.…”

“…In line with our assumption that the damage mechanism is predominantly thermal [11], we neglect the preceding de-excitation and charge transfer processes and assume that all atoms are in their electronic ground state, giving an upper bound for crystal stability. Similar approaches have been used to analyze the formation of tracks by swift heavy ion impact, where strong local heating due to electronic excitations also leads to melting and restructuring [18,19].…”

Surface topographical and structural analysis of Ag+-implanted polymethylmethacrylate

“…Many researchers have examined the modification produced by highly charged ions on the surface of a wide variety of materials, including CaF 2 [7], Mica [8], GaAs [9], Al 2 O 3 , and KBr [10], in terms of formation of craters, pits, and hillocklike structures.…”