Published online by Cambridge University Press: 24 June 2008
This paper reports the characterization of lithium tantalite (LiTaO3) thin films deposited by sol gel process. Thin films were deposited on (001) sapphire substrates by spin coating. In order to study the effect of annealing temperature on the structural and optical properties, the films were annealed at several heating temperatures, ranging from 600 to 750 °C. From X-ray diffraction measurements it is confirmed that LiTaO3 films are highly c-axis oriented, the line width and the intensity of the (006) peak are sensitive to the variation of the annealing temperature and the best results were found at 700 °C. From SEM pictures it is found that the grain size increases from 100 to 200 nm when the annealing temperature is increased to 700 °C. From the optical transmittance and absorbance measurements, the band gap energy was extrapolated at about 4.6 eV which closely agrees with the LiTaO3 bulk value. Fourier transform infrared (FTIR) reflectivity and Raman backscattering were used as two complementary experiments to probe the zone center optical phonons in the lithium tantalite thin films.