Bestimmung der OH⁻‐Konzentration in LiNbO₃‐Kristallen durch Protonenresonanz‐Untersuchungen

PE-Layers and Proton Diffusion Profiles in LiNbO3 Investigated with Fourier-IR and Second Harmonic Generation

“…For the above values we get f,,, (OH) = 1.6 x lo-, in fair agreement with recent determinations [8]. This must be compared to an oscillator strength of OH in TiO, [22] of f,,, = 3.8 x l o T 2 and to a value determined by Bollman et al [23,24],f,,, (OH in LiNbO, bulk) = 1.2 x l o p 3 from extrapolating NMR measurements to low concentrations. Similar small values off,,, have been found only for OH-in alkali halides [22].…”

Chemical environment and occupation sites of hydrogen in LiMO3

“…However, at reduced concentrations of 1.25 at% (1.2 Â 10 21 cm À3 ), the double defect can be excluded for LiTaO 3 , which is still beneficial for LiNbO 3 at even lower hydrogen concentrations according to the general trend. It should be noted that in as-grown crystals, hydrogen concentrations in the range of B10 18 -10 20 cm À3 are expected, 95,96 which is significantly lower than our calculated concentrations. We therefore assume that there is no hydrogen clustering for ideal stoichiometric LiMO 3 cells.…”

On the quantification of hydrogen in lithium metal oxides

“…We show different challenges of material preparation and compare our data on C-LiTaO 3 with existing NMR data on C-LiNbO 3 . 63…”

“…This way the quality of the crystals and their properties are concluded from the OH − band, but how much hydrogen is present in the crystals has only been contradictorily documented for PE-and C-LiNbO 3 . [63][64][65][66][67][68] FT-IR spectroscopy can only make qualitative statements about the OH − stretching vibration. For an accurate quantitative statement on the hydrogen content of a material based on IR vibrational bands, the absorption band area must be calibrated with an externally determined hydrogen concentration value.…”