We study the nucleation of GaN islands grown by plasma-assisted molecular-beam epitaxy on AlN(0001) in a Stranski-Krastanov mode. In particular, we assess the variation of their height and density as a function of GaN coverage. We show that the GaN growth passes four stages: initially, the growth is layer-by-layer; subsequently, two-dimensional precursor islands form, which transform into genuine three-dimensional islands. During the latter stage, island height and density increase with GaN coverage until the density saturates. During further GaN growth, the density remains constant and a bimodal height distribution appears. The variation of island height and density as a function of substrate temperature is discussed in the framework of an equilibrium model for Stranski-Krastanov growth.
@article{arxiv.cond-mat/0311050,
title = {Nucleation and Growth of GaN/AlN Quantum Dots},
author = {C. Adelmann and B. Daudin and R. A. Oliver and G. A. D. Briggs and R. E. Rudd},
journal= {arXiv preprint arXiv:cond-mat/0311050},
year = {2017}
}