Energetic particle induced luminescence of Al2O3

In-situ observations of ion induced luminescence of sapphire (Al2O3) specimens are conducted with respect to incident energy, fluence and ion species. The luminescence spectra showed three band emissions centered at 335, 420 and 650 nm assigned to F+, F and 2nd order of F+ with some contribution of F-2-type defects, respectively. Comparing with TRIM calculations it is clearly demonstrated that the ion induced luminescence of Al2O3 is simply caused by the electron excitation by the incident ion. The observed luminescence intensity changed with the ion fluence; F center monotonously decreased and mostly disappeared, whereas F+ first increased to a maximum and then gradually decreased to a nearly steady value after prolonged irradiation. Following the heavy irradiation the total luminescence intensity was reduced to less than 1/2 of the initial value owing to the clustering of the defects and possibly the precipitation of Al. When the fluence is translated to dpa, changes of the luminescence intensity with dpa for D+ and He+ irradiations are very similar, indicating that implanted D atom has little effect on the luminescence as assigned the luminescence centers of F and F+ to single oxygen vacancies.