Rheotaxial growth and vacuum oxidation—Novel technique of tin oxide deposition—In situ monitoring of oxidation process

• Pure SnO2 nanolayers are firstly deposited by rheotaxial growth and vacuum oxidation (RGVO).
• RGVO method allows obtaining the SnO2 nanolayers of precisely controlled stoichiometry/nonstoichiometry.
• The obtained RGVO SnO2 nanolayers exhibit of extended internal surface open for active gases interaction.

Within this work a novel preparation method of SnO2 nanolayers based on in situ rheotaxial growth and vacuum oxidation (RGVO) is presented for the first time. The SnO2 films were characterized with the use of X-ray Photoelectron Spectroscopy (XPS), and Atomic Force Microscopy (AFM). A special emphasis was given to control the oxidation conditions in order to obtain the RGVO SnO2 nanolayers of controlled stoichiometry/nonstoichiometry for potential application. Performed XPS studies demonstrated that the RGVO SnO2 nanolayers are of extremely high purity and exhibit the controlled nonstoichiometry depending on the additional controlled oxidation. The variations of RGVO SnO2 nanolayers׳ surface chemistry, determined also by XPS, were in a good correlation with the variation of their surface morphology controlled by AFM experiments.