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Dimitrakopulos G.P.♦, Kalesaki E.♦, Kioseoglou J.♦, Kehagias T.♦, Lotsari A.♦, Lahourcade L.♦, Monroy E.♦, Häusler I.♦, Kirmse H.♦, Neumann W.♦, Jurczak G., Young T.D., Dłużewski P., Komninou Ph.♦, Karakostas T.♦, Morphology and strain of self-assembled semi-polar GaN quantum dots in (1112) AlN,
JOURNAL OF APPLIED PHYSICS, ISSN: 0021-8979, DOI: 10.1063/1.3506686, Vol.108, pp.104304-1-9, 2010 Abstract:
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 (11-2)-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. Keywords:
Quantum dots, Transmission electron microscopy, III-V semiconductors, High resolution transmission electron microscopy, Epitaxy Affiliations:
| Dimitrakopulos G.P. | - | Aristotle University of Thessaloniki (GR) | | Kalesaki E. | - | Aristotle University of Thessaloniki (GR) | | Kioseoglou J. | - | Aristotle University of Thessaloniki (GR) | | Kehagias T. | - | Aristotle University of Thessaloniki (GR) | | Lotsari A. | - | Aristotle University of Thessaloniki (GR) | | Lahourcade L. | - | CNRS (FR) | | Monroy E. | - | CNRS (FR) | | Häusler I. | - | Humboldt-Universität zu Berlin (DE) | | Kirmse H. | - | Humboldt-Universität zu Berlin (DE) | | Neumann W. | - | Humboldt-Universität zu Berlin (DE) | | Jurczak G. | - | IPPT PAN | | Young T.D. | - | IPPT PAN | | Dłużewski P. | - | IPPT PAN | | Komninou Ph. | - | Aristotle University of Thessaloniki (GR) | | Karakostas T. | - | Aristotle University of Thessaloniki (GR) |
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