Theory of Rayleigh-wave amplification in piezoelectric semiconductor films— quantum theoretical approach

Abstract

A quantum theory is presented for the interaction of the Rayleigh waves with electrons in piezoelectric semiconductor films. Our aim is to investigate the amplification of the Rayleigh waves with frequencies higher than 1 GHz. The effect of the finite relaxation time of electronic states is properly considered in the range of frequencies satisfying $\omega \tau <1\mathrm{}$. A numerical example is developed for an $n$-type GaAs epitaxial layer on a semi-insulating GaAs substrate taking the relaxation time into account phenomenologically.