Low-temperature growth of epitaxial LiNbO3 films on sapphire (0001) substrates using pulsed laser deposition

Abstract

Epitaxial LiNbO₃ films were grown on sapphire (0001) substrates using pulsed laser deposition. A single‐crystal LiNbO₃ was used as a target. Growth behaviors of the LiNbO₃ films deposited at various deposition conditions such as temperature, oxygen pressure, and annealing condition were studied. Deposition temperature is found to be an important parameter which enables us to grow LiNbO₃ films without the LiNb₃O₈ phase: formation of the Li deficient phase can be suppressed by depositing the films at temperature below 500 °C. Oxygen pressure during deposition influences crystallographic orientations of the films. An x‐ray pole figure shows that epitaxial LiNbO₃ film was grown, but with twin boundaries. The ordinary refractive index of the film was found to be 2.28, which is in good agreement with the bulk value.