Acoustic Harmonic Generation in Nondegenerate Semiconductors

A phenomenological theory is developed to study acoustic wave second harmonic generation in piezoelectric as well as nonpiezoalectric semiconductors, and derive optimum conditions for maximum harmonic generation. The results show that second harmonic flux is maximum at higher frequencies in nonpiezoelectric semiconductors, and at lower frequencies in semiconductors exhibiting both piezoelectricity and deformation potential, as compared to the case of pure piezoelectric materials, while it is a maximum at v _d = v _s for both the coupling mechanisms.