Structural and optical properties of self-assembled GaN/AlN quantum dots

This paper reviews our studies of wurtzite GaN/AIN quantum dots grown by MBE via the Stranski-Krastanow mode. High resolution transmission electron microscopy shows that dots are dislocation free, without any evidence of interdiffusion effects. They form arrays of truncated hexagonal pyramids (height of 4 nm and base diameter of 15 nm), nucleating next to threading dislocations on top of a wetting layer, and exhibiting vertical correlation between different quantum dot layers. The existence of polarization and piezoelectric fields of several MV/cm is demonstrated by photoluminescence and decay time measurements. Nevertheless quantum dots are found to be the most efficient emitters in nitrides at room temperature. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.