A RAPID-RESPONSE SAW-BASED SENSOR FOR H2S DETECTION

This paper developed a method to improve the response velocity of Surface acoustic wave (SAW)-based H2S sensor employing SnO2 film. Due to a SAW-based detector is endowed with inherent high sensitivity, it is adopted to detect low-level inorganic gas. However, this detector's speed of response and recovery is very low when it is operating in room temperature. Our work is motivated by the observation that the sensor inertia can be accelerated by changing working temperature and constructing digital sensor model. Firstly, A set of evaluation experiments are established. SnO2/CuO composite film and 36 degrees YX-LiTaO3 are adopted as waveguide layer and substrate of love wave sensor respectively. Secondly, a sensor's response speed is measured when it works at specified 160 degrees C. Experimental result shows good repeatability for sensing H2S. The response in 160 degrees C shows more than 100 times of that in home temperature. Lastly, a simple sensor model is constructed to determine concentration value in a relative short time. The fitting results show that the whole response procedure can be predicated in shorter time for six times. The evaluation model is demonstrated as a promising method to accelerate the response velocity for SAW-based H2S sensor.