Multiple sensor array based on pure and surface modified WO3 thin films for e-nose application.

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]