Nanostructuring of BaF2 (1 1 1) surfaces by single slow highly charged ions

The creation of surface nanostructures in BaF2 (1 1 1) surfaces was studied after irradiation with slow highly charged Xe ions from the Dresden-EBIT (electron beam ion trap). After irradiation, the crystals were investigated by scanning force microscopy (SFM). Using specific ion parameters, the topographic images show nanohillocks emerging from the surface. Additionally, we used the technique of selective chemical etching to reveal the lattice damage created by ion energy deposition below and above threshold needed for surface hillocks formation. The role of both potential and kinetic energy as well as a comparison with results for swift heavy ion irradiations of BaF2 single crystals are presented.