Droplet epitaxy of zinc-blende GaN quantum dots

Abstract

Zinc-blende GaN quantum dots were grown on 3C-AlN(0 0 1) by a vapor–liquid–solid process in a molecular beam epitaxy system. We were able to control the density of the quantum dots in a range of 5×10 8–5×10 12 cm −2. Photoluminescence spectroscopy confirmed the optical activity of the GaN quantum dots in a range of 10 11–5×10 12 cm −2. The data obtained give an insight to the condensation mechanism of the vapor–liquid–solid process in general, because the GaN quantum dots condense in metastable zinc-blende crystal structure supplied by the substrate, and not in the wurtzite crystal structure expected from free condensation in the droplet.