Fourier transform infrared spectroscopy (FTIR) reflectance spectra were measured using a Bruker Vertex70 FTIR spectrometer, with a globar MIR light source and a DLaTGS detector, the software used here is Bruker OPUS 7.5. The incident spolarized light at an angle of 60° with respect to the sample surface normal. The spectra were acquired at room temperature, after a 30 min N2 purge, with 2 cm -1 resolution and averaged over 50 scans. A thin film of gold was used as reference. The FTIR peaks were fitted using a Lorentzian profile and linear base line using SciDAVis software (version 1.22). X-ray diffraction (XRD) was used to investigate the structural properties and the crystallographic relationship to the buffer layer and the film orientation. All diffractograms were recorded using Cu Kα radiation (Cu Kβ removed by a nickel filter).