Acoustoelectronic phenomena in the systems with quantum size effects

Abstract

The theory of electron absorption and amplification of surface acoustic waves and of the acoustoelectric effect (both longitudinal and transverse) is presented for the layered structure piezoelectric-thin semiconductor film for which the conditions of size quantization are fulfilled. The case of high frequencies ql ⪢ 1 ( q is the wave number of the acoustic wave, l the mean free path of the electrons) is considered. The expression is found for the “effective” dielectric constant of the film, ϵ eff, which is used in the Ingebrigtsen method of calculation of acoustoelectronic phenomena in layered structures. In the limiting cases of degenerate and non-degenerate semiconductors the explicit expressions for the electron absorption (amplification) coefficient of the surface acoustic waves are found and it is shown that it may suffer giant quantum oscillations as function of the film thickness. Acoustoelectric voltage and acoustoelectric current (both longitudinal and transverse) also may suffer analogous oscillations.