Thin sol–gel SiO2–SnOx–AgOy films for low temperature ammonia gas sensor

Thin SiO2–SnOx–AgOy films were prepared, up to 60–100 nm thick, by means of the sol–gel technology and characterized by a variety of analytical techniques. It is shown that the films have an amorphous structure with an inclusion of crystallites of Ag and Sn oxides. The conductance of the films is rather sensitive to the presence of NH3 impurity in air at lower operating temperatures in the range of 20–50 °C.