Defects creation in sapphire by swift heavy ions: A fluence depending process

International audienceSingle crystals of sapphire (α-Al2O3) were irradiated at GANIL with 0.7 MeV/amu xenon ions corresponding to an electronic stopping power of 21 keV/nm. Several fluences were applied between 5 X 1011 and 2 X 1014 ions/cm2. Irradiated samples were characterized using optical absorption spectroscopy. This technique exhibited the characteristic bands associated with F and F+ centers defects. The F centers density was found to increase with the fluence following two different kinetics: a rapid increase for fluences less than 1013 ions/cm2 and then, a slow increase for higher fluences. For fluences less than 1013 ions/cm2, results are in good agreement with those obtained by Canut et al. [B. Canut, A. Benyagoub, G. Marest, A. Meftah, N. Moncoffre, S.M.M. Ramos, F. Studer, P. Thévenard, M. Toulemonde, Phys. Rev. B 51 (1995) 12194]. In the fluences range: 1013–1014 ions/cm2, the F centers defects creation process is found to be different from the one evidenced for fluences less than 1013 ions/cm2