Design and Analysis of Silicon Nanowire Array Based on SAW Gas Sensor

Abstract

AbstractEstimating the sensitivity of a surface acoustic wave (SAW) gas sensor accurately and effectively is essential for gas sensing applications. In this paper, the sensitivity of a SAW gas sensor without sensitive material, as well as with a sensing layer comprised of silicon and silicon nanowire arrays (SiNWA), are studied and analyzed via finite element method. Correspondingly, the effect of the length of the sensing material and the gas concentration on the SAW gas sensor sensitivity is being investigated. The proposed SiNWA-based SAW sensor showed high sensitivity at a length of 700 nm, owing to the high surface-to-volume ratio of sensing layer material. Meanwhile, it demonstrated a frequency shift of 270.3 kHz when exposed to a 5000-ppm carbon dioxide gas concentration through the sensing layer. Overall, the SAW gas sensor with SiNWA sensing layer provided significant sensing response.KeywordsSAW gas sensorSilicon nanowire arrayFinite element analysisGas concentration