Theory of the Acoustoelectric Current in A Quantum Well

The acoustoelectric (AE) current in a quantum well (QW) is investigated for an acoustic wave whose wavelength is smaller than the mean free path of the electrons and the hypersound in the region (where is the acoustic wave number). The nonlinear dependence of the AE current jac on the frequency of acoustic wave, and the temperature T of the system is obtained by using the Boltzmann kinetic equation. The analytical expression for the AE current jac is calculated in case the relaxation time of momentum is constant approximation. Numerical calculations are done, and the result is discussed for a typical AlAs/GaAs/AlAs QW. The result indicates that the existense peaks in QW may be due to the transition between mini-bands. The dependence of the AE current on the temperature T and the Fermi energy with a maximum at T=50K, for. These findings agree with the experimental results. All the results are compared with the normal bulk semiconductor and superlattice to highlight the difference