The modification of LiTaO3 crystal by low-energy He-ion implantation

The effects of He-ion implantation on the surface morphology and transmittance of LiTaO3 single crystals are investigated. The samples were implanted with 250 keV He-ion at different fluences at room temperature. The results show that the surface morphology and transmittance of implanted samples strongly depend on the ion fluence and the time when the samples expose to the air up to 60 days. When the fluence is above 1.0 × 1016 He+/cm2, the transmission spectra indicate that a high concentration of defects is created. 3D-profile images show that at the higher fluence a great many triangular stripes appear on the surface of the samples. After 60 days, the recovery of the transmittance occurs and varies with the fluence. For the sample at the fluence of 5.0 × 1016 He+/cm2, the raised stripes on the surface evolve into narrow cracks. Regional exfoliation, however, occurs on the surface of the sample with the fluence of 1.0 × 1017 He+/cm2. According to the experimental results and simulation of SRIM 2008 code, the evolvement of defects and the behavior of He are discussed.

► LiTaO3 crystal was implanted by 250 keV He+.
► We report the surface and transmittance of LiTaO3 change with the fluence and time.
► New phenomena (self-splitting, self-exfoliation, self-recovery) occurred.
► Evolvement of defects and the behavior of helium were discussed.