[en] GaN quantum dots (QDs) grown in semipolar (11-22) AlN by plasma-assisted molecular-beam
epitaxy were studied by transmission electron microscopy (TEM) and scanning transmission
electron microscopy techniques. The embedded (11-22)-grown QDs exhibited pyramidal or
truncated-pyramidal morphology consistent with the symmetry of the nucleating plane, and were delimited by nonpolar and semipolar nanofacets. It was also found that, in addition to the (11-22) surface, QDs nucleated at depressions comprising {10-11} facets. This was justified by ab initio density functional theory calculations showing that such GaN/AlN facets are of lower energy compared to (11-22). Based on quantitative high-resolution TEM strain measurements, the three-dimensional QD strain state was analyzed using finite-element simulations. The internal electrostatic field was then estimated, showing small potential drop along the growth direction, and limited localization at most QD interfaces.
Research center :
Aristotle University of Thessaloniki
Disciplines :
Physics
Author, co-author :
Dimitrakopulos, George; Department of Physics, Aristotle University of Thessaloniki
KALESAKI, Efterpi ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Kioseoglou, Joseph; Department of Physics, Aristotle University of Thessaloniki
Kehagias, Thomas; Department of Physics, Aristotle University of Thessaloniki
Lotsari, Antiopi; Department of Physics, Aristotle University of Thessaloniki
Lahourcade, Lise; CEA-CNRS Group “Nanophysique et Semiconducteurs,” INAC/SP2M/NPSC, CEA-Grenoble
Monroy, Eva; CEA-CNRS Group “Nanophysique et Semiconducteurs,” INAC/SP2M/NPSC, CEA-Grenoble
Hausler, Ines; Institut für Physik, Humboldt-Universität zu Berlin, AG Kristallographie
Kirmse, Holm; Institut für Physik, Humboldt-Universität zu Berlin, AG Kristallographie
Neumann, Wolfgang; Institut für Physik, Humboldt-Universität zu Berlin, AG Kristallographie
Jurczak, Gregor; Institute of Fundamental Technological Research of the Polish Academy of Sciences
Young, Toby David; Institute of Fundamental Technological Research of the Polish Academy of Sciences
Dłużewski, Pavel
Komninou, Philomela; Department of Physics, Aristotle University of Thessaloniki
Karakostas, Theodoros; Department of Physics, Aristotle University of Thessaloniki
