Creation of nanodots on mica surfaces induced by highly charged xenon ions

Experiments on nanostructure formation on muscovite mica surfaces irradiated by highly charged Xe ²⁹⁺ ions with a beam energy of 0.58 MeV and Xe ³⁰⁺ ions with two beam energies (0.6 MeV and 4.8 MeV) have been carried out on the 320 kV ECR platform at the Institute of Modern Physics (IMP), Lanzhou. The created nano-sized structures have been imaged using tapping mode atomic force microscopy. Hillock-like structures are clearly visible at the surface of the mica irradiated by Xe ²⁹⁺ ions (at 0.58 MeV) below the charge state threshold reported in earlier experimental investigations with a height (∼1.6 nm) nearly equal to the one observed by Xe ³⁰⁺ ions (at 0.6 MeV). Moreover when mica is irradiated by Xe ³⁰⁺ ions (at 4.8 MeV), regular nanodots have been observed with a surprisingly larger height of 3.3 nm, nearly the double than the one created by the impact of Xe ³⁰⁺ ions with kinetic energy of 0.6 MeV. The possible mechanism of insulator surface modification is discussed.