Doping of SnO2 films during spray pyrolysis deposition: influence on gas sensing characteristics and thermal stability of film structure

Abstract

The study of additives’ influence on both the gas sensing characteristics and thermal stability of SnO2 films structure was the main goal of a research. A conception of such approach is based on a statement that the appearance in gas sensing matrix of elements with different physical-chemical properties gives additional factors influencing the important parameters of metal oxide. For SnO2 films deposition used spray pyrolysis from 0.2 M SnCl4-water solutions. Gas sensing characterization showed that the doping could significantly improve both sensitivity and selectivity of gas sensors. However, the optimization of gas response takes place only for concentrations of additives in the range from 0.05-3 wt.%. The superfluous concentration of these additives sharply reduces the gas response. On the base of results of structural study of doped SnO2 films it was concluded that observed worsening of gas sensing characteristics is a consequence of second metal oxide phase formation in SnO2 matrix.