Raman study of collective plasmon-longitudinal optical phonon excitations in cubic GaN and Al(sub x)Ga(sub 1-x)N epitaxial layersdd

The Raman scattering in cubic GaN doped with Si and in intrinsically doped cubic Al(sub x)Ga(sub 1-x)N alloys were used to study the plasmon-longitudinal optical (LO) phonon collective excitations. The specific asymmetry of the corresponding Raman lines, associated with the dispersion of the coupled excitations was clearly detected in GaN.