Fabrication of GaN dot structure by droplet epitaxy using NH 3

Abstract

In GaN dots grown by droplet epitaxy using NH 3, the relation between growth temperature, and size, density, and degree of nitridation was investigated. As growth temperature increased from 390 to 700 °C, both enlargement of dot size and a drop in dot density were observed, which seemed to be caused by both migration and evaporation of Ga atoms. In contrast, post-growth annealing at 700 °C under an NH 3 atmosphere for the sample grown at 520 °C had the effects of remarkably increasing dot density, reducing dot size, and improving nitridation of the grown dots. The mechanism of GaN dot growth by droplet epitaxy using NH 3 is discussed, and the effectiveness of the post-growth annealing under an NH 3 atmosphere is shown.