Growth of InN quantum dots on N-polarity GaN by molecular-beam epitaxy

We investigated the growth behaviors of InN quantum dots (QDs) on N-polarity GaN by molecular-beam epitaxy. The N-polarity growth has been intentionally used to raise the temperature to facilitate formation of high-quality dots. It was found that the InN QDs could be grown up to 550°C the Stranski–Kastanov growth mode with the wetting layer thickness of about 1 monolayer, which was confirmed by the simultaneous in situ observations of reflection high-energy electron diffraction and spectroscopic ellipsometry. The density and the diameter of typical InN QDs grown at 450–550°C were the order of 1011cm−2 and 15–20nm, respectively.