Heating of Rayleigh Surface Acoustic Wave Devices in 128°YX LiNbO_3 and ST X Quartz Substrates

摘要

Heating of surface acoustic wave (SAW) devices can be utilized for micro-heating and in microreactor applications, but is a disadvantage in biosensing. In this contribution, we fabricate SAW devices in 128° YX LiNbO_3 and ST X quartz substrates with same physical dimensions, having center frequencies approximately of 96 MHz and 78 MHz, respectively to study heating at several power levels. We demonstrate droplet heating is caused by acoustic wave streaming resulting from the coupling between fluid and solid. A 10 μm water droplet on a 128° YX LiNbO_3 device can be heated up by 3.3°C with 15 dbm power level, whereas, the ST X quartz device is only heated up by 0.7°C. Our work illustrates that the 128° YX LiNbO_3 substrate shows great potential for liquid heating applications. The ST quartz substrate is better suited for removal of non-specifically bound (NSB) proteins in biosensing applications, especially if shear horizontal SAWs propagating in the orthogonal direction are utilized for biosensing.