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Model‐based geometry reconstruction of quantum dots from TEM
Author(s) -
Maltsi Anieza,
Koprucki Thomas,
Niermann Tore,
Streckenbach Timo,
Tabelow Karsten,
Polzehl Jörg
Publication year - 2018
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201800398
Subject(s) - quantum dot , nonlinear system , geometry , stochastic geometry , scattering , materials science , statistical physics , computer science , classical mechanics , physics , optics , mathematics , nanotechnology , quantum mechanics , statistics
The reconstruction of geometric properties of semiconductor quantum dots (QDs) from imaging of bulk‐like samples (thickness 100‐300 nm) by transmission electron microscopy (TEM) is a difficult problem. A direct reconstruction by solving the tomography problem is not feasible due to the limited image resolution (0.5‐1 nm), the highly nonlinear behavior of the dynamic electron scattering, nonlocal effects due to strain and strong stochastic influences due to uncertainties in the experiment. We present a mathematical model for the numerical simulation of TEM images. This includes elasticity theory to obtain the strain profile coupled with the Darwin‐Howie‐Whelan equations, describing the propagation of the electron wave through the sample. Furthermore, we introduce a novel concept for 3D model‐based geometry reconstruction of QDs from TEM images. The approach includes a geometric model for the QD configuration in real space, a database of simulated TEM images and a statistical procedure for the estimation of the geometric properties and the classification of QD types.