Influence of liquid properties on the performance of S-0-mode Lamb wave sensors: A theoretical analysis
2015 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, Vol. 208, 212-219 p.Article in journal (Refereed) Published
Sensors based on thin film electroacoustic (TEA) devices have emerged as a promising alternative to quartz crystal microbalance and surface acoustic wave devices, in view of sensibility, miniaturization and easy integration. TEA devices include quasi-shear film bulk acoustic resonators (QS-FBAR) and S-0 mode Lamb wave resonators (S-0-LWR) based on AlN films. Despite the work done on the application of TEA devices as in-liquid biological and chemical sensors, a theoretical framework for S-0-LWRs properly describing their sensing mechanisms is still needed. Here we validate a finite element analysis model on QS-FBARs and study the sensing mechanisms of S-0-LWRs in liquid media. We show that S-0-LWRs can sense changes in the dielectric permittivity of the liquid and demonstrate different sensitivities to viscosity and density. A complementary assessment of the S-0-LWRs losses, dependent in a non-specific manner on the square root of the density viscosity product, provides the ability to discriminate density from viscosity changes on the entire device surface. Finally, with an S-0-LWR optimization study we show that resolution improves with the decrease of the membrane thickness; however, a trade-off between sensitivity, quality factor and membrane fragility has to be considered.
Place, publisher, year, edition, pages
2015. Vol. 208, 212-219 p.
Thin film electroacoustic, AlN resonator, Lamb wave, Sensing mechanisms, In-liquid, Optimization
Chemical Sciences Physical Sciences Engineering and Technology
Research subject Engineering Science with specialization in Electronics
IdentifiersURN: urn:nbn:se:uu:diva-241381DOI: 10.1016/j.snb.2014.11.026ISI: 000346000500029OAI: oai:DiVA.org:uu-241381DiVA: diva2:783532