Nonlinear acoustoelectric effect in a semiconductor superlattice

The acoustoelectric effect in a semiconductor superlattice (SL) has been studied for a hypersound in the region ql much greater than 1 (where q is the acoustic wave number and I is the electron mean free path). A nonlinear dependence of the acoustoelectric current j(ac) on the constant electric field E is observed. It is noted that when the electric field is negative the current j(ac) rises, reaches a peal; and falls off. On the other hand, when the electric field is positive the current decreases, reaches a minimum and then rises. A similar observation has been noted for an acoustoelectric interaction in a multilayered structure resulting from the analysis of Si/SiO2 structure. The dominant mechanism for such a behaviour is attributed to the periodicity of the energy spectrum along the SL axis.