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

Self-assembled GaN quantum dots (QDs) grown on Al0.15Ga0.85N using Si as an ti-surfactant were investigated by resonant Raman scattering. Phonons of Ga N 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 Al0.23G a0.77N after the deposition of an increasing amount of Si anti-surfactant, i.e., the morphological transition from a GaN quantum well (2D) to GaN quan tum dots (OD), was also investigated.