Design and analysis of high-sensitivity multilayered structure surface acoustic wave sensor for dichloromethane gas detection

Micro- and nano-sensors are key devices used in various fields from medical to environmental science. With the progress of micro- and nano-fabrication technology and the use of newly designed materials, sensor design has been significantly improved, leading to the development of high-performance gas sensors. A novel multilayer structure gas sensor based on surface acoustic wave (SAW) is proposed for the detection of volatile harmful gas dichloromethane. The gas sensing characteristics of single-layer and multilayer SAW sensors were studied by using finite element method. The influence of geometric parameters on the sensor performance was analyzed and the optimal structure was determined. The propagation characteristics of SAW were obtained by transient simulation of the whole structure. The sensitivity of the sensor is evaluated by placing the sensor in different concentrations of dichloromethane gas. The results show that the sensitivity of the PIB/AlN/Diamond/Si SAW gas sensor is as high as 66.9 ppm/Hz under the optimal geometry structure, which is nearly 30 times higher than that of other single-layer and multilayer SAW sensors. This work provides a good solution for the design of high-sensitivity SAW sensors.