Sensitivity analysis of multilayered C-axis inclined zigzag zinc oxide thin-film bulk acoustic resonators for CO2 concentration monitoring

This paper proposes a theoretical analysis of an innovative C-axis inclined zigzag multilayered ZnO thin-film bulk acoustic resonator (FBAR) for CO2 concentration monitoring. Analytical study is carried out with 3-D linear piezoelectric equations with appropriate boundary conditions. Numerical results show that the thickness of FBAR has a constant influence on the sensitivity while C-axis inclined angle has a significant influence on the sensitivity for the longitudinal mode of multilayered (double-layered in this paper) FBAR CO2 sensor. The selectivity and sensitivity of the proposed sensor can be further improved by the dopant in ZnO FBAR for real environment monitoring.