Stranski-Krastanow growth and optical properties of self-assembled GaN quantum dots

GaN self-assembled quantum dots (QDs) with high quality and high density have been grown by low-pressure metalorganic chemical vapor deposition under very low V/III ratio. Depositing over the critical thickness of 4 monolayers of GaN, we observed the transition from the two-dimensional to three-dimensional growth mode. The density of the QDs could be changed between 10(9) and 10(10)cm(-2). The typical diameter and height of the QDs were 20 nm and 2 nm, respectively. The size of the QDs was controlled to a considerable extent by changing the growth temperature. Moreover, we observed two photoluminescence peaks from both the QDs and the wetting layer at room temperature. This result clearly demonstrates that the GaN QDs were formed under the Stranski-Krastanow growth mode.