Acoustofluidics Based on ZnO/Al Plate Surface Acoustic Wave Devices with Enhanced Performances

In this paper, we report acoustofluidics based on zinc oxide (ZnO)/Al plate surface acoustic waves (SAWs) and compare their performances with those of ZnO/Si SAWs with the same electrode configurations. Results show that ZnO/Al (1.5 mm thick) SAWs achieve a lower threshold pumping power and have better pumping performances than those of ZnO/Si SAWs due to their larger Rayleigh angle and higher electromechanical coupling coefficients. Wavelength effects on pumping performances of ZnO/Al plate SAWs are also investigated and a larger wavelength leads to a lower threshold pumping power. Moreover, we also study effects of Al plate thickness on pumping performances and results show that ZnO/Al plate SAWs present better pumping performances than those of ZnO/Al foil SAWs.