Swift heavy ion irradiation effect on the surface of sapphire single crystals

Surface changes in sapphire single crystals with four different orientation s produced by irradiation with Kr (305 MeV), Xe (595 MeV) and Bi (710, 557, 269 and 151 MeV) ions have been studied by means of atomic force microscop y and thermo-stimulated exo-electron emission (TS EEE). It was observed tha t individual surface defects with density corresponding to the ion fluence have been detected only for Bi ions with energy higher than 269 MeV. At the highest surface ionizing density values of 41 and 35 keV/nm, these defects were found to have a complicated structure-the hillock surrounded by borde r ring or hillock with cavity on the top. The TS EEE measurements show that all studied crystals are characterized by TS EEE curve depending on crysta llographic orientation and irradiation dose. At the same time, some general features in the TS EEE data for all crystallographic orientations are obse rved. (C) 2001 Elsevier Science Ltd. All rights reserved.