Elucidation of fluorine in SnO2:F sprayed films by different spectroscopic techniques

The aim of the present work is to explore a suitable spectroscopic technique for accurate determination of fluorine in the fluorine doped tin oxide (SnO2:F) thin films whereas accurate determination of fluorine in SnO2:F thin films was not clarified in the literature. For this purpose, fluorine doped tin oxide (SnO2:F) thin films were prepared on cleaned glass substrates by spray pyrolysis technique using SnCl4 and NH4F as precursor for SnO2 and fluorine dopants respectively. Five different spectroscopic techniques which are mostly used for characterization of the different thin films were used in order to understand the actual behavior of fluorine inside SnO2:F thin films. These techniques are electron probe microanalysis (EPMA), scanning electron microscope (SEM), wavelength dispersive X-ray fluorescence (WDXRF), X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering (RBS). Acceptable agreements of quantitative analysis of fluorine in SnO2:F thin films was obtained by using WDXRF and RBS techniques. It was found that, the real fluorine content in SnO2:F thin films is not representing the content of the prepared solutions for spray pyrolysis. The real content of fluorine represents only ∼10% from the imbedded concentration of fluorine whereas ∼90% was lost during the deposition process of the thin films using spray pyrolysis technique.