SFM study of ion-induced hillocks on LiF exposed to thermal and optical annealing

Single crystals of LiF were irradiated at 10 different temperatures from room temperature to 780 K with Pb ions of 4.1 MeV/u. The irradiated surfaces were analyzed with scanning force microscopy, which revealed ion-induced hillocks with diameters of similar to20 nm and with heights of a few nm, Above 450 K, the number of hillocks strongly decreased with irradiation temperature. No hillocks were created under irradiation at 780 K. In addition, LiF samples irradiated at room temperature with Ni (2.5 MeV/u) and U ions (11.1 MeV/u) were bleached with UV-light on part of the crystal surface. In the bleached area, the characteristic F- and F-2-centers disappeared, whereas the mean diameter and height of the hillocks did not show any significant change. (C) 2003 Elsevier B.V. All rights reserved.