Synthesis of Bi2O3 and Bi4(SiO4)3 thin films by the sol-gel method

Bi2O3 thin films were prepared by dipping silica slides in ethanolic solutions of tris(2,2'-6,6'-tetramethylheptane-3,5-dionato)bismuth(I [Bi(dpm)(3)] [1] and heating in air at temperatures less than or equal to 500 degrees C. Bi-4(SiO4)(3) homogeneous thin films were obtained from the reaction of the bismuth oxide coating with the silica glass substrate at temperatures higher than 700 degrees C. For heat treatments at temperatures between 600 degrees C and 700 degrees C, Bi2SiO5 coatings were obtained. The composition and microstructure evolution of the films were determined by Secondary Ion-Mass Spectrometry (SIMS), X-Ray Photoelectron Spectroscopy (XPS) and Glancing Angle X-Ray Diffraction (GA-XRD). The synthesis procedure was reproducible and allowed the control of the Bi2O3 phase composition. Moreover, the thin film annealing parameters were correlated with the formation of bismuth silicates, among which Bi-4(SiO4)(3) (BSO) is very appealing for the production of fast light-output scintillators [2].