On phonon confinement effects and free carrier concentration in GaN quantum dots

Self-assembled GaN quantum dots (QDs) grown on Al^0.15Ga^0.85N using Si as anti-surfactant were investigated by resonant Raman scattering. Phonons of GaN QDs of different sizes were probed selectively by using laser excitation energies of 3.53 and 5.08 eV. Phonon confinement effects were evidenced in GaN QDs of 2-3 nm height. Resonant Raman scattering on GaN grown on Al^0.23Ga^0.77N after the deposition of an increasing amount of Si anti-surfactant, i.e., the morphological transition from a GaN quantum well (2D) to GaN quantum dots (0D), was also investigated.