X-ray photoemission spectroscopy study of the surface chemistry of laser-assisted chemical vapour deposition SnOx thin films after exposure to hydrogen

In this paper we present the results of X-ray Photoemission Spectroscopy (XPS) study of the surface chemistry of Laser-assisted Chemical Vapour Deposition (L-CVD) deposited tin oxide SnOx thin films before and after subsequent exposure to molecular hydrogen (hydrogenation) at room and elevated temperature up to 800 K. As-deposited L-CVD tin oxide thin films exhibited a nonstoichiometric composition with a relative concentration [O]/[Sn] equal to 1.29 +/- 0.05. After exposure to 10(5) L of hydrogen at room temperature the relative concentration [0]/[Sn] was almost the same. After the same exposure to hydrogen at elevated temperature the relative concentration [O/Sn] decreases what confirms the effect of drastic reduction to the almost stoichiometric tin oxide SnO thin films. This evident reduction of L-CVD tin oxide thin films was confirmed by the shape analysis of corresponding XPS Sn3d(5/2) and O1s peaks using the deconvolution procedure in which the different contribution of O-Sn2+ and O-Sn4+ bondings were determined.