Propagation of leaky surface acoustic waves in a layered piezoelectric semiconductor structure

Some piezoelectric materials, such as ZnO and AlN, have not only piezoelectric properties but also semiconductor property. In this paper, an analytical solution of the leaky surface acoustic waves (LSAW) is developed for the structure composed of piezoelectric substrate boned with piezoelectric semiconductor (PSC) film using the partial wave method. Furthermore, the dispersion, loss, and attenuation curves of the LSAW in the composite structure have been obtained by combining the boundary conditions at the top of the film and the continuity conditions on the interface between the film and the substrate. Numerical examples illustrate the effects of PSC film thickness-to-wavelength ratio, steady-state carrier concentration, and biasing electric field on the dispersion, loss, and attenuation curves of LSAW in AlN film/LiNbO₃ substrate. In addition, we conducted simulation by means of the PDE module in COMSOL. The theoretical results are consistent with the simulations, which could be helpful for the design of surface acoustic wave devices based on PSC materials.