Propagation characteristics of shear horizontal surface acoustic waves in (11 2 0) ZnO film/silica glass substrate structures

This paper presents the propagation characteristics of the shear horizontal surface acoustic wave (SH-SAW) in ZnO (0deg, 90deg, psi) (11 2macr 0) textured ZnO films. ZnO (0deg, 90deg, 0deg) film/interdigital transducer (IDT) electrode/silica glass substrate structures were fabricated by RF magnetron sputtering. Experimental results demonstrate that SH-SAW was clearly excited in these structures. We also theoretically estimated the electromechanical coupling coefficient K² in the ZnO (0deg, 90deg, psi) film/silica glass substrate structure. The theoretical results show that the IDT electrode/ZnO (0deg, 90deg, 55deg) film/silica glass substrate structure had a relatively high K² value of 3.4%. Moreover, the shear horizontal displacement component of the SH-SAW in this structure is much larger than the transverse and longitudinal displacement components. This structure could be used in SH-SAW sensors for evaluating the electrical properties of liquids.