Direct signature of strained GaN quantum dots by Raman scattering

We report on a Raman study of strained wurtzite GaN quantum dots embedded i n AlN spacers. Various laser excitations between 2.33 and 3.81 eV were used , which allows for selective probing of the dots, through resonant enhancem ent of the Raman signal. A direct signature of the A(1) (LO) and E-2 phonon s of the GaN dots has been obtained. The measured phonon frequencies show t hat the mean in-plane strain inside the GaN dots approaches the lattice mis match between GaN and AlN. (C) 2001 American Institute of Physics.