Characterisation of YBa2Cu3O6+x films grown by the trifluoro-acetate metal organic decomposition route by infrared spectroscopy

Infrared reflectivity measurements have been performed at T=300 K on c-axis oriented YBa2Cu3O6+x films obtained by deposit of trifluoroacetate precursors on (100)-LaAlO3 single crystalline substrates. A detailed simulation of the infrared spectra acquired on the thin films based on the use of an appropriate complex dielectric function model is proposed here. It allows us to determine with a single experiment the thickness and the residual porosity of the layers. To reinforce the statement of the infrared simulations, the results have been compared with the film porosity obtained by scanning electron microscopy imaging. Moreover the local grain orientation has been checked by polarized Raman microspectroscopy. Finally, the three complementary experimental ways give consistent results that justify the present approach.