Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 43: Poster Session: Quantum Dots and Wires - Preparation and Characterization / Devices (incl. Laser) / Ultrafast Phenomena
HL 43.12: Poster
Dienstag, 27. März 2012, 09:30–12:30, Poster D
3D-Determination of InGaAs Quantum Dots in Cross-Section TEM Specimens — •Maren Schiersch1, Tore Niermann1, André Strittmatter2, Tim David Germann2, Gernot Stracke2, Jan-Hindrik Schulze2, Udo W. Pohl2, and Michael Lehmann1 — 1Institut für Optik und Atomare Physik, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany — 2Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
Because Quantum Dots (QDs) offer a variety of applications, they are a current hot research topic. TEM investigations of QDs structures are usually performed in cross-section. However, in cross-section the QD-layer is only imaged in projection. So it is not possible to access the number of QDs or density at all. To investigate the distribution of QDs we apply a method using tilt series [1]. At increased tilt angles, the planar QD distribution becomes visible using dark-field images in the light of the chemical sensitive reflection {200}. As result the QD size and density as well as the thickness of the specimen can be evaluated from the recorded tilt series. Furthermore, the angular distribution, the distribution of QDs and thus the distance of nearest neighbors are determined. This method is applied on specimens with InGaAs-QDs buried in GaAs with different In-concentrations. This work is supported by the DFG Collaborative Research Centre 787.
[1]: Beanland, R. et al.: Electron tomography of III-V quantum dots using dark field 002 imaging conditions. In: Journal of Microscopy. The Royal Microscopical Society, February 2010 (237), p. 148-154