A study of Love wave devices in ZnO/Quartz and ZnO/LiTaO3 structures

Love wave devices are very promising for sensing applications because of high sensitivity. In this paper, ZnO thin films doped with lithium (Li) and magnesium (Mg) were deposited on the 42°45′ ST-cut quartz and 36° YX-LiTaO3 substrates by RF magnetron sputtering technique. XRD, SEM, and AFM measurements investigated characteristics of the films. Under different conditions such as doping content, layer thickness, and substrate temperature, the phase velocity, temperature coefficient of frequency, electromechanical coupling coefficient and sensitivity of Love wave devices in ZnO/Quartz and ZnO/LiTaO3 structures are presented. The maximum sensitivities of ZnO/Quartz and ZnO/LiTaO3 are much higher than the SiO2/Quartz and SiO2/LiTaO3 structures reported.