IR observation on O–D vibration in LiNbO 3 and LiTaO 3 single crystal irradiated by 3 keV [formula omitted

Abstract

The behavior and existence states of deuterium irradiated into LiNbO 3 and LiTaO 3 single crystals were studied by in situ FT-IR observations on multiple O–D vibration peaks and by TDS on the desorption behavior of deuterium. Two O–D vibration peaks were observed in both LiNbO 3 and LiTaO 3, one at 2610–2615 cm −1 and the other at 2560–2570 cm −1. The former O–D vibration was attributed to –OD − affected by Nb defect in LiNbO 3 or Ta defect in LiTaO 3. For attribution of the latter O–D vibration, two candidates remained, –OD − affected by Li vacancy and –OD − of interstitial D +. By heating after the ion irradiation, the irradiated deuterium was mainly desorbed as hydrogen molecular forms (D 2 and HD). The –OD − affected by Nb defect in LiNbO 3 or Ta defect in LiTaO 3 had a higher desorption temperature than the other –OD −s. The two materials showed similar results in the existence states and the desorption behavior of irradiated D +, although some differences were observed due to more formation of Nb defect in LiNbO 3 than Ta defect in LiTaO 3 by displacement. It was indicated that the release temperature of hydrogen isotopes is heightened by the influence of M defect in ternary lithium oxides (Li x MO y ).