Berlin 2018 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 7: Microstructure of thin films / TEM-based Nanoanalysis
KFM 7.8: Vortrag
Montag, 12. März 2018, 17:40–18:00, E 124
Model-based geometry reconstruction of quantum dots from TEM — •Anieza Maltsi1, Thomas Koprucki1, Karsten Tabelow1, and Tore Niermann2 — 1Weierstraß-Institut für Angewandte Analysis und Stochastik, Berlin, Germany — 2Inst. f. Optik und Atomare Physik, TU Berlin, Berlin, Germany
The growth of semiconductor quantum dots (QDs) with desired electronic properties would highly benefit from the assessment of QD geometry, distribution, and strain profile in a feedback loop between growth and analysis of their properties. One approach to assist the optimization of QDs consists in imaging bulk-like samples (thickness 100-300 nm) by transmission electron microscopy (TEM) instead of high resolution (HR) TEM of thin samples (thickness 10 nm). For HRTEM the relaxation of the lamella-like samples may strongly modify the strain field or the preparation may potentially destroy the QDs. However, a direct 3D geometry reconstruction from TEM of bulk-like samples by solving the tomography problem is not feasible due to its limited resolution (0.5-1 nm), the highly nonlinear behavior of the dynamic electron scattering and strong stochastic influences due to uncertainties in the experiment, e.g. excitation conditions. Here, we present a novel concept for 3D model-based geometry reconstruction (MBGR) of QDs from TEM images. The approach includes an appropriate model for the QD configuration in real space, a database of simulated TEM images and a statistical procedure for the estimation of QD properties and classification of QD types based on machine learning techniques.