Interface E ects on the Vibrational Properties of 3 C { InN / 3 C { AlN Superlattices

Calculation of the Raman spectra of zinc{blende InN/AlN superlattices were carried out assuming the existence of an interface region with thickness Æ varying from zero to three monolayers. Frequency shifts up to 80 cm 1 were observed for some of the optical frequencies when Æ = 3. Many peaks appearing at the low frequency side, shift toward the center position of the spectrum. As a consequence, pairs of the Raman modes become quasi{degenerate giving rise to highly prominent structures in the spectrum, for Æ = 2 and 3. These e ects are tracked to localization of atomic displacements mainly at the interface regions.