Inelastic light scattering by phonons in hexagonal GaN-AlN nanostructures

Two selected examples have been chosen to illustrate the ability of non-res onant Raman scattering to probe phonons in hexagonal GaN-AlN artificial str uctures. The angular dispersion of polar phonons is investigated in a long period GaN-AlN superlattice and compared with the results of calculations b ased on a dielectric continuum model. On the other hand, the Raman signatur e of the self-assembled GaN quantum dots and of the ALN spacers of a multi- layered struct;re is used to determine the strain field in the stucture. Th e dots are shown to be fully strained on the ALN lattice parameter while th e spacers exhibit on the average a slight tensile strain.