NaCl Formation in Spray-Deposited SnO2:F Films

Pyrolytically deposited SnO{sub 2} films on soda glass were analyzed by SEM, XRD, SAM, and XPS. The films were deposited at different temperatures and time periods. Some films revealed large NaCl crystals situated in holes or on the surface; other films were topologically smooth. However, small NaCl crystallites were observed in all films. The XPS analyses revealed that all Cl was bound to Na in the form of NaCl and two Auger Cl peaks were observed in all samples. The lower energy Auger Cl peak resulted from bulk NaCl, whereas the second peak, shifted by 10 eV toward higher kinetic energy, was associated with the SnO{sub 2}/NaCl interface. Annealing of the SnO{sub 2} films revealed a large decrease in Cl concentration. The excess Na is associated with the SnO{sub 2} matrix, most likely in two forms, interstitially in the film lattice as well as in the form of Na{sub 2}SnO{sub 3}.