Smooth interface effects on the Raman scattering in zinc-blende AlN/GaN superlattices

Raman spectra of (AlN)(8-delta)/(AlxGa1-xN)(delta)/(GaN)(8-delta)/(AlxGa1-xN)(delta) superlattices with interface thickness varying between delta = 0 and delta = 3 are calculated. The influence of the nonabrupt interface related broadening is described in the complete range of scattering, with special attention to the modes giving stronger contribution to the Raman intensity. It is shown that the dispersion of folded acoustic phonons does not change appreciably with the interface smoothing. For delta = 0 the Raman spectra display new peaks due to the enhancement of some confined optic modes.