The Structural Modification of LiTaO₃ Crystal Induced by 100-keV H-ion Implantation

The effects of 100 keV H-ion implantation on the structure of LiTaO₃ crystal are investigated by Raman and UV/VIS/NIR spectroscopies. The implantation fluence is in the range from 1.0×10¹³ to 1.0×10¹⁷ H⁺/cm². The experimental results show the dependence of the crystal structure on ion fluence. It is found that the structural modification of the LiTaO₃ crystal is due to two processes. One is H?ions occupying lithium vacancies (V_Li), which is predominant at a fluence less than 1.0×10¹⁴ H⁺/cm². This process causes the reduction of negative charge centers in the crystal and relaxation of distortion in the local lattice structure. The other is the influence of defects created during implantation, which plays a dominant role gradually in the structural modification at a fluence larger than 1.0×10¹⁵ H⁺/cm².