Surface acoustic wave propagation and acoustoelectric interaction in multilayered piezoelectric semiconductors

In the past years, the acoustoelectric interaction has been used in a number of different devices such as acoustic amplifiers, acoustoelectric convolvers and acoustic coupled transport devices. Recent developments in synthesized semiconductor superlattices with high quality heterostructures have been found to be useful in a new generation of high performance devices such as the High Electron Mobility Transistor. The objective of this paper is to extend the use of these superlattices to acoustoelectric devices. A complete theory of acoustoelectric interaction in layered piezoelectric semiconductor has been developed. The acoustic propagation equations have been solved together with the continuity, transport and Poisson equations. The free carrier transport properties are accounted for using a mobility tensor to describe the two-dimensional behavior. The acoustical and electrical boundary conditions have been used to obtain mechanical displacement and electric field expressed in terms of Bloch functions. The effect of longitudinal D.C. applied field on SAW attenuation or amplification is also considered.