Electron-energy-loss spectra were recorded from cross-sectional transmission electron microscopy samples of Li+-irradiated KTiOPO4 single crystals. By evaluating the intensity in the pre-edge shoulder of the OK ionization edge, the depth distribution of O vacancies in radiation-damaged KTiOPO4 was monitored. Li+ irradiation at 295K and Li+ irradiation at 100K generate very similar defect profiles except for an additional superficial maximum in the room-temperature irradiated sample. Vacancy distributions in the O sub-lattice could be monitored on the nanometre scale by the method introduced. The methodology was potentially applicable to a wide range of materials, when pertinent defect-sensitive features in electron-energy-loss spectra were evaluated, and its sensitivity was expected to become further improved with the availability of monochromated electron sources in transmission electron microscopes.

Depth Distribution of Oxygen Vacancies in 1MeV Li+-Irradiated KTiOPO4. T.Höche, H.J.Kleebe, F.Schrempel, W.Wesch: Philosophical Magazine Letters, 2002, 82[11], 599-608