Raman spectra of a wurtzite GaN (6.3 nm)-AlN (5.1 nm) superlattice have bee
n recorded under visible excitation. When the orientation of the phonon wav
evector is varied, the angular dispersion of polar phonons from the superla
ttice is clearly evidenced. These experimental data are found to be in good
agreement with the results of a previous calculation based on a dielectric
continuum model, taking into account the strain of the two types of layers
, which predicts dispersive interface and quasi-confined modes. (C) 2001 El
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