Optical Investigation of Cu Diffusion Depth in LiNbO3 Crystals Under High-Temperature Treatment
The paper presents the results of investigations of optical absorption spatial changes in congruent bulk LiNbO3 crystals in 300–1500 nm spectral region along X, Y, and Z directions caused by high-temperature annealing in presence of copper ions. Additional optical absorption was measured at different depths that allows to estimate the spatial distribution of dopant ions. As it is shown, the spatial distributions of absorption caused by copper ions (Cu+ and Cu2+) have got maxima at the distances about 400–600 μm from the crystal edge. The formation of copper oxide ultrafine nanoparticles in the surface layer of LiNbO3 is confirmed by XRD analysis.
KeywordsLithium niobate Redox treatment Diffusion Quasi-chemical reactions Optical absorption
The work was supported by Ukrainian Ministry of Education and Science (scientific research project DB/EMSh) and joint Indian-Ukrainian project M/201-2017. The authors are grateful to Dr. Iwan Solskii (SRC ‘Carat’) for growing the crystal for investigations and to Mr. Vasyl Baluk for XRD measurements.
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