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Fabrication of a 2 × 4 multiple sensor array based on SnO2 thin films was demonstrated. SnO2 thin films were deposited on Al2O3 substrates and modified selectively using Au and CuO by sputtering. The sensor array was tested for its gas sensing characteristics towards H2S. The maximum sensor response (S=52) was observed in case of Au modified SnO2 thin films. By the surface modification using Au there is increase in the sensor response at all temperature. With the increase in temperature, sensor response decreases. [ABSTRACT FROM AUTHOR]

A 2 × 3 sensor array based on pure, Au and CuO modified (two of each kind) WO3 films was fabricated for e-nose application. Effect of surface modification has been investigated and correlated with the observed sensor response values. The sensor array was able to detect H2S,NH3 and NO selectively based on the sensor response pattern exhibited by the sensor array. WO3 sensor film modified with CuO exhibited a maximum sensitivity towards H2S (S = 92, 10 ppm, 250°C) while pure WO3 films exhibited better sensing characteristics towards NO (S=2.3, 10 ppm, 300°C) and NH3 (S=4.5, 50 ppm, 300°C). The shape of the curve remains unaltered by the change in the concentration of the gas. The shape and position of the combined response curve could be used to determine an unknown gas both qualitatively and quantitatively. [ABSTRACT FROM AUTHOR]