Two successive effects in the interaction of nanocrystalline SnO2 thin films with reducing gases

Interaction of pure and doped (Pd. Pt, Cu. Ni) nanocrystalline SnO2 thin fi lms with different reducing gases (H-2, CO, C3H8/C4H10) was studied in a te mperature range of 30-400 degrees C in situ by the electrical response proc essing. Two successive effects of conductance growth were found. It is supp osed that the more pronounced second effect may be associated with tin diox ide and doping metal oxides transformations resulting from the consumption of lattice oxygen in redox reactions on the SnO2 grain surface. The variati on of the chemical state of elements during annealing in different gas atmo spheres was determined by the X-ray Photoelectron Spectroscopy (XPS) method . A special procedure of thin film annealing was proposed to reduce the ind uction period necessary for the second peak to appear. (C) 2000 Elsevier Sc ience S.A. All rights reserved.