Structure and Properties of Hydrogen Sulfide Sensors Based on Thin Tin Dioxide Films

Structural, electrical, and gas-sensitive characteristics of thin films (~100 nm) of tin dioxide containing Sb, Au, and Ni impurities in the bulk and dispersed Au clusters on the surface were studied. For the films prepared by magnetron sputtering, the size of SnO 2 grains is of the order of 40–125 nm, and introduction of Au in the synthesis step leads to the Au segregation in the form of nanosized inclusions of the second phase. The sensors are highly sensitive to H 2 S in a wide concentration interval, 0.5–100 ppm. Operation of the sensors in the thermo-cycling mode ensures increased response to low H 2 S concentrations (<5 ppm) in the cooling cycle. The values of the sensor response remained high in long-term tests (180 days and more).