In-situ poling of lithium niobate films on silicon wafer by applying a low electric field during pulsed laser deposition

Completely c-oriented LiNbO3 (LN) films have been fabricated on p-type Si(111) wafer coated with SiO2 buffer by applying a low electric field of Ef=8 V cm−1 during pulsed laser deposition (PLD). X-ray photoelectron spectroscopy (XPS) analysis indicates that the stoichiometry of the film is in good agreement with that of the bulk LN target materials. The crystal structure of the as-grown film is tested by X-ray diffraction (XRD) using a θ–2θ scan. The surface of the LN film is smooth, dense and crack-free, no large droplets are observed by scanning electron microscope (SEM). The X-ray energy dispersive spectrometer (XREDS) analysis to the different area of cross-section of the LN film shows that there are no variation of composition with the depth. Favourable optical waveguiding properties of the films are demonstrated by a prism coupler method.