Fabrication and Room Temperature Volatile Organic Compounds Sensing Performance of ZnO-Based Surface Acoustic Wave Gas Sensor

In this study, surface acoustic wave (SAW) sensor platforms were fabricated with various electrode structure design on piezoelectric substrates using microelectromechanical system (MEMS) fabrication techniques. After the fabrication and characterization of SAW sensor platforms, ZnO nanorods' sensing layer was coated on devices by seed-mediated hydrothermal method for using in volatile organic compounds' (VOCs) pollutant detection at room temperature. Sensor tests were performed against acetone, hydrogen cyanide (HCN), hydrogen sulfide (H2S), ammonia, and relative humidity in the concentration range between a few particles per million (ppm) and particle per billion (ppb). In the ppb regime, the highest sensor response was observed to be 13.113 Hz for 750-ppb acetone at room temperature, with an approximate response and recovery time as 29.97 and 30.01 min, respectively. The gas sensing characteristics of ZnO-based SAW sensor were investigated in detail regarding the various sensing mechanism parameters such as mass sensitivity and elasticity effect.