Recharging processes, radiation induced strain and changes of OH− bands under H+ ion implantation in Ti doped lithium niobate

A systematic analysis of variations in structural and optical characteristics of Z-cut plates of titanium doped congruent lithium niobate single crystals implanted with 120 keV proton beam at various fluences of 1015, 1016 and 1017 protons/cm2 is presented. Through, high resolution X-ray diffraction, atomic force microscopy, Fourier transform infrared and UV–visible–NIR analysis of congruent lithium niobate, the correlation of properties before and after implantation are discussed. HRXRD (0 0 6) reflection by Triple Crystal Mode shows that both tensile and compressive strain peak are produced by the high fluence implantation. A distinct tensile peak was observed from implanted region for a fluence of 1016 protons/cm2. AFM micrographs indicate mountain ridges, bumps and protrusions on target surface on implantation. UV–visible–NIR spectra reveal an increase in charge transfer between Ti3+/Ti4+ and ligand oxygen for implantation with 1015 protons/cm2, while spectra for higher fluence implanted samples show complex absorption band in the region from 380–1100 nm. Variations of OH− stretching vibration mode were observed for cLN Pure, cLNT2% virgin, and implanted samples with FTIR spectra. The concentration of OH− ion before and after implantation was calculated from integral absorption intensity. The effect of 120 keV proton implantation induced structural, surface and optical studies were correlated.