Inelastic light scattering by phonons in hexagonal GaN-AiN nanostructures

Two selected examples have been chosen to illustrate the ability of non-resonant Raman scattering to probe phonons in hexagonal GaN–AlN artificial structures. The angular dispersion of polar phonons is investigated in a long period GaN–AlN superlattice and compared with the results of calculations based on a dielectric continuum model. On the other hand, the Raman signature of the self-assembled GaN quantum dots and of the AlN spacers of a multi-layered structure is used to determine the strain field in the stucture. The dots are shown to be fully strained on the AlN lattice parameter while the spacers exhibit on the average a slight tensile strain.