High Sensitivity Semiconductor NO 2 Gas Sensor Based on Mesoporous WO 3 Thin Film

A NO 2 gas sensor based on mesoporous WO 3 thin film with low operating temperatures and its sensing characteristics are reported. The mesoporous WO 3 thin film exhibits regular pores with an average pore size of 5 nm andspecific surface area of 151 m 2 /g. Excellent sensing properties are found upon exposure to 3 ppm of NO 2 at 35-100°C for mesoporous WO 3 thin film. The sensor response is 180 for 3 ppm NO 2 at 100°C. The ability to sense NO 2 at such low temperatures is attributed to the large surface area (151 m 2 /g) that offers many active sites for reaction with NO 2 molecules.

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