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

This paper reviews our studies of wurtzite GaN/AIN quantum dots grown by MB E via the Stranski-Krastanow mode. High resolution transmission electron mi croscopy shows that dots are dislocation free, without any evidence of inte rdiffusion effects. They form arrays of truncated hexagonal pyramids (heigh t of 4 nm and base diameter of 15 nm), nucleating next to threading disloca tions on top of a wetting layer, and exhibiting vertical correlation betwee n different quantum dot layers. The existence of polarization and piezoelec tric fields of several MV/cm is demonstrated by photoluminescence and decay time measurements. Nevertheless quantum dots are found to be the most effi cient emitters in nitrides at room temperature. (C) 2000 Academie des scien ces/Editions scientifiques et medicales Elsevier SAS.