Preliminary study on pyroelectric lithium tantalite by a novel electrostatic spray pyrolysis technique

In this paper, we report the first results obtained for pyroelectric LiTaO3 thin films prepared on silicon substrates by electrostatic spray pyrolysis (ESP), a simple, low cost and efficient technique not widely used for LiTaO3 deposition, using lithium acetylacetonate and tantalum ethoxide in a mixture of methanol. The effect of the growth and annealing temperature on the structural and optical properties has been investigated. X-ray diffraction measurements have shown that LiTaO3 thin films became preferentially oriented in the (0,1,2) plane after annealing treatment in an oxygen environment using the rapid thermal processing. On the other hand, a thermal stress's modeling is performed to observe the effect of growth temperature on the as-deposited films and the substrates. The SEM images have shown that the film heat-treated at 600 °C became more homogeneous and smoother than that before annealing. The optical phonon modes of the LiTaO3 thin films have been also investigated using infrared reflectivity (FTIR) and Raman spectroscopy.