Synthesis of LiNbO3 thin films by using niobium oxalate

ABSTRACT In this study we investigated the preparation of thin films of lithium niobate (LiNbO3), by using ammonium niobium oxalate - (NH4H2NbO (C2O4) .3H2O - in the synthesis of the precursor resin, by the polymeric precursor method (Pechini). The crystalline phase formation was investigated by XRD analysis, revealing a strong influence of the stoichiometry of the resin and thermal treatment on the formation of LiNbO3 phase. A comparative analysis with previous studies in the literature and experimental data observed for powder reveals that this strong influence on the phase formation of the films is probably related to the use of oxalate precursor as starting material. The morphology of the films was investigated by scanning electron microscopy with field emission gun (FEG-SEM); its revealed a porous structure, a qualitative analysis of elements present in the film was based on the EDS spectra analysis (SEM-EDS), revealing the presence of residual carbon in the final samples.