Optimum acoustic wave second-harmonic generation in piezoelectric semiconductors

The phenomenological approach has been used to study analytically the acoustic wave second harmonic generation in piezoelectric semiconductors in the presence of the d.c. electric and an oscillating electromagnetic field (OEF). It has been suggested that the second harmonic acoustic flux (SHAF) can be enhanced considerably by the application of an OEF polarized in the direction of the propagating acoustic wave. The SHAF exhibits a maximum at Ω = ω, where Ω is the frequency of the OEF and ω is the frequency of the acoustic wave. The SHAF also shows a maximum at d.c. electric fields for which the average drift velocity of the carriers is equal to the velocity of sound. It is found that for a typical case of n-type nondegenerate InSb (77°K, n = 2·5 × 10¹⁴ cm^?3) that the SHAF is enhanced by a factor of 10³ over its value in the absence of OEF. The present analysis is valid in the low frequency region only (i.e. ql ? 1).