Reversible metallization of SnO2 films under hydrogen and oxygen containing atmospheres

P.M. DESIMONE; C.G. DÍAZ; J.P. TOMBA; C.M. ALDAO; M.A. PONCE

JOURNAL OF MATERIALS SCIENCE

SPRINGER

Lugar: Berlin; Año: 2016 vol. 51 p. 4451 - 4461

0022-2461

The adsorption of different gases onto tin oxidefilms surfaces promotes electrical conductance variations.Films chemiresistive properties depend on the intergranularbarrier heights and on the concentration of non-stoichiometricdefects that, in the case of tin oxide, are mainlyoxygen vacancies. We found that film exposures to an H2-containing atmosphere over 400 C led to unusual resultsthat cannot be explained resorting to regular interpretations.By means of Raman spectroscopy and XRD characterization,we show that, at high enough temperatures,when films are exposed to hydrogen, the tin dioxide convertsinto tin monoxide and metallic tin. Then, when filmsare exposed to air atmosphere, the oxygen diffuses into thegrains converting the metallic tin back into tin dioxide.These findings are consistent with electrical measurements.