Investigation of barium titanate thin films on MgO substrates by second-harmonic generation

Abstract

Barium titanate (BaTiO3) thin films grown by the metalorganic chemical vapor deposition (MOCVD) technique on MgO substrates have been investigated by second-harmonic generation at an incident wavelength of 1.064 μm. Transmission electron microscopy was used to show that substrate quality and pretreatment (annealing) has a strong influence on microstructure and optical properties of these films due to nucleation effects during MOCVD growth. Angular dependence of second-harmonic signal indicates both a- and c-textured growths in this film/substrate system. Stress-induced stabilization appears to determine the orientation of the microcrystallites in the films. Corona poling does not result in a preferred orientation of the film. Effective d coefficients as high as 2.13 pm/V have been obtained from as-grown films.