Epitaxial growth of LiNbO3-LiTaO3 thin films on Al2O3

Abstract

Epitaxial thin films of LiNbO3 and LiTaO3 were grown on sapphire substrates by the rf-magnetron sputtering method. Structural characterization was made by several spectroscopic measurements: x-ray diffraction, Raman scattering, and optical absorption. We obtained epitaxial thin films with lattice-mismatched strained layers, without misfit defects which are usually created at the interface. Impurity-ion (Nd3+ and Cr3+) doped films were also grown; these films had larger refractive indices than the pure films. Furthermore, the heteroepitaxial thin films of up to 10 alternating LiNbO3/LiTaO3 layers were successfully grown, and their periodic structures were studied by optical second-harmonic generation.