Influence of the sol–gel growth parameters on the optical and structural properties on LiNbO3 samples

We report on the structural, morphological and optical characterization of Er doped lithium niobate (LiNbO3) grown in a glass matrix prepared by sol–gel route. The samples were grown from a mixture with nominal composition of 91SiO2–4Li2O–4Nb2O5–1Er2O3 (Er:LN) and the crystallization process was followed up in the temperature range between 500 °C and 750 °C. The Er:LN samples start to crystallize at temperatures above 600 °C and besides the LiNbO3 crystalline phase sub micron ErNbO4 precipitates were identified by X-ray diffraction and Raman measurements. A comparison with glass matrices grown without NbO2 or Li2O was carry out in order to identify both the structural and optical properties of the Er:LN samples. The fingerprint emission lines of Er3+ ion in the Er:LN samples are discussed in terms of distinct crystalline environments for the Er ion in samples.