Resonant Raman scattering on self-assembled GaN quantum dots

Self-assembled GaN quantum dots grown on Al0.15Ga0.85N using Si as antisurfactant have been investigated by resonant Raman scattering. Phonons of GaN quantum dots of different sizes and the Al0.15Ga0.85N barrier layer were probed selectively by varying the laser excitation energy from 3.53 to 5.08 eV. Phonon confinement effects were studied on GaN quantum dots of 2-3 nm height. We show that although grown using Si (a common donor for GaN) as an antisurfactant, only a small electron concentration is present in the GaN quantum dots. Implications on the role of Si for the formation of the GaN quantum dots will be discussed. (C) 2001 American Institute of Physics.