GaN/AlN quantum dots (QDs) grown on sapphire/GaN substrate have been realized by low-pressure metalorganic chemical vapor deposition. The influence of the growth conditions, postgrowth annealing ambience, and roughness of AlN template surface has been investigated. QDs with 3–10 nm height, 40–100 nm diameter, and density from 1×1011 down to 1×108 cm−2 were achieved by adjusting the growth temperature, V/III ratio, and growth time. For the formation of QDs, the postgrowth annealing in H2 is more favorable than that in NH3; however, it results in a bad surface of wetting layer and therefore is not suitable for device fabrication. When rough-surface templates were used, small-sized dots with the same density as obtained on smooth-surface templates could be found besides some large clusters. An intense photoluminescence peak of QDs is observed at 15 K and up to room temperature.
No takes yet. Share an insight, caveat, or question.
Zhang et al. (2008) studied this question.