Sol gel synthesis of multiphase lanthanum oxicarbonate and langasite thin films

Precursors of lanthanum oxide and of (3La2O3, 5Ga2O3, SiO2) system were first elaborated then thermally decomposed into polycrystalline lanthanum oxide and langasite La3Ga5SiO14. The as prepared lanthanum oxide powder was then hydrated and carbonated to give hydroxicarbonates: thermal decomposition of these complex system La2O3-X(OH)y(CO3)z was studied by Fourier Transform infrared spectroscopy. Spin coating process applied to these precursors was optimized to elaborate thin films of lanthanum oxicarbonate La2O2CO3, lanthanum oxide La2O3 and langasite, on silicium substrates (Si-(001)). Thin films are partly textured. Making use of same spin coating process, multiphase thin films of langasite covered with La2O3 particles were obtained.