Synthesis and Characterization of the β-BaB2O4 Phase Obtained by the Polymeric Precursor Method

A modified polymeric precursor method based on the Pechini process was used to synthesize β-BaB2O4 (β-BBO) crystalline phase. D-sorbitol (C6H14O6) was used as a polymerizing agent to avoid the loss of boron during the samples' calcination and crystallization. The β-BBO stoichiometric crystalline phase was only obtained when sorbitol was added to the solution. The results of Raman spectroscopy show that the amorphous phase is only completely eliminated when the samples are heat-treated at 750°C for 20 h. Thin films of β-BBO phase displaying a preferred orientation were obtained when crystallized at 750°C for 2 h and deposited on sapphire substrate.