Analysis of efficient VOCs gas detection SAW sensor based on ZnO/diamond/Si multilayered structure

This study investigates the Surface Acoustic Wave (SAW) characteristics of gas sensor devices based on the ZnO/Diamond/Si layered structure, utilizing Finite Element Method (FEM) simulations through the Comsol Multiphysics package. Analysis of device performance, including phase velocities, electromechanical coupling coefficient (K2), and reflectivity, is conducted for both Rayleigh and Sezawa wave modes. Additionally, the sensor's sensitivity to gas concentration in the air is examined for various Volatile Organic Compounds (VOCs) using a thin Polyisobutylene (PIB) layer for sensor demonstration. The study highlights a notable sensitivity enhancement of the SAW sensor achieved through the Sezawa wave mode compared to the Rayleigh mode. For instance, a sensor sensitivity of 38.85 Hz/ppm is observed for the Sezawa mode in contrast to 14.30 Hz/ppm for the Rayleigh mode, as demonstrated with standard Tetrachloroethene (PCE).