Raman study of SrBi2Ta2O9 thin films

Thin films of SrBi2Ta2O9 (SBT) were deposited on Si using Sol-Gel technique . The thicknesses of the films 200 nm (SBT2) and 400 nm (SBT4), respectivel y. SEM were studies showed most of the grains in the film are smaller than 0.1 mu. FTIR reflectivity measurements of the samples showed bands around 1 260, 936(for SBT2), 955(for SBT4), 770, 600 cm(-1) Micro Raman spectra show s bands corresponding to the SET materials, but some frequency shifts and b roadening were observed. Particularly, the band around 818 cm(-1), which co rresponds to a stretching of the TaO6 octahedron, was found to change from 785 to 827 cm(-1) This change seems to be related to the Ta-O bond length.