Wang Linlin, Wang Yuan, Tietze Max, Madeira Bernardo Pereira, Martins Rui P, Mak Pui-In, Chanut Nicolas, Rajagopal Divya, Sugihara Masaya, Ameloot Rob, Wang Chen
ESAT-MNS, KU Leuven, Leuven, 3001, Belgium.
Institute of Microelectronics (AMSV), University of Macau, Taipa, Macau, China.
Microsyst Nanoeng. 2025 Apr 23;11(1):69. doi: 10.1038/s41378-025-00917-3.
This paper explored the practical utility of gas sensing applications based on the multi-degree-of-freedom (Multi-DoF) bulk acoustic wave (BAW) resonant sensors, including 1, 2, and 3-DoF devices, where piezoelectric actuation and sensing methods were adopted. Zeolitic imidazolate framework-8 (ZIF-8) was chosen for the adsorption and desorption of the ethanol vapor, thereby facilitating the gas sensing mechanism and introducing the external mass changes to the multi-DoF resonating system. Similar to conventional quartz crystal microbalance (QCM) gas sensors, the frequency shift of all the devices (1, 2, and 3-DoF devices) was tracked to characterize the sensitivity. Besides, for the 2 and 3-DoF devices, the amplitude ratio (AR) change was also recorded and observed with an enhancement in performance. Compared with the state-of-the-art gas sensor based on 2-DoFcapacitively coupled resonators, the presented devices achieved better Q factor in air, stability, and resolution in terms of both frequency shifts and AR changes. The dominant mass change (dominant stiffness change in the state-of-the-art) of the proposed resonant devices matched well with the theoretical mass sensing principle, which is both predictable and crucial for the accurate modeling of the practical mass sensor. Furthermore, a lower ethanol vapor concentration from 0.1% to 2% was successfully detected by the proposed 2-DoF device, demonstrating even better sensing performance than that of the state-of-the-art.
本文探讨了基于多自由度（Multi-DoF）体声波（BAW）谐振传感器的气敏应用的实际效用，包括采用压电驱动和传感方法的1、2和3自由度器件。选择沸石咪唑酯骨架-8（ZIF-8）用于乙醇蒸汽的吸附和解吸，从而促进气敏机制并将外部质量变化引入多自由度谐振系统。与传统的石英晶体微天平（QCM）气体传感器类似，跟踪所有器件（1、2和3自由度器件）的频率偏移以表征灵敏度。此外，对于2和3自由度器件，还记录并观察到幅度比（AR）变化，性能有所提高。与基于2自由度电容耦合谐振器的最新气体传感器相比，所展示的器件在空气中实现了更好的品质因数、稳定性以及在频率偏移和AR变化方面的分辨率。所提出的谐振器件的主要质量变化（最新技术中的主要刚度变化）与理论质量传感原理匹配良好，这对于实际质量传感器的精确建模既具有可预测性又至关重要。此外，所提出的2自由度器件成功检测到了0.1%至2%的较低乙醇蒸汽浓度，展示出比最新技术更好的传感性能。
