Defects creation in sapphire by swift heavy ions: a fluence depending process
Résumé
Single 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 5×1011 and 2×1014 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. [Phys. Rev. B 51 (1995) 12194]. In the fluences range: 1013 to 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.