The synthesis, thermal, structural & optical characterisations of Y0.9Er0.1(BO3)4 amorphous thin films deposited on fused silica substrates by spin coating are reported. The film process starts from solutions prepared by two chemical methods: either the polymeric precursor method or by sol-gel processing. These initial solutions were first polymerised and the resulting powders were analysed by differential scanning calorimetry while the deposits were characterised by x-ray diffraction. The levels of hydroxyl groups in the thin films were evaluated using Fourier transform infrared spectrometry as a function of temperature. The refractive indexes were obtained indirectly by an envelope method using interference fringes of the transmission spectra. Finally, luminescence spectra between 1400 & 1600nm were obtained using an excitation wavelength of 980nm.
