Vacuum deposited WO3 thin films based sub-ppm H2S sensor

A simple method of vacuum deposition using W foils has been utilized to fabricate Au-incorporated WO3 thin film sensors. Incorporation of Au has been demonstrated to improve both the sensitivity and the selectivity of the sensor films towards H2S. The effect of operating temperature, Au loading and gas concentrations have been investigated and correlated with the observed sensitivity values to determine the optimum conditions for realizing H2S sensor with better sensing properties. The sensor film containing 2.32 at.% Au detected H2S selectively with an enhanced sensitivity of S = 16 (1 ppm) at an operating temperature of 250 °C. The enhanced response kinetics has been confirmed further using Raman and work function measurements.