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- ItemNumerical simulation of TEM images for In(Ga)As/GaAs quantum dots with various shapes(Dordrecht [u.a.] : Springer Science + Business Media B.V, 2020) Maltsi, Anieza; Niermann, Tore; Streckenbach, Timo; Tabelow, Karsten; Koprucki, ThomasWe present a mathematical model and a tool chain for the numerical simulation of TEM images of semiconductor quantum dots (QDs). 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. We perform a simulation study on indium gallium arsenide QDs with different shapes and compare the resulting TEM images to experimental ones. This tool chain can be applied to generate a database of simulated TEM images, which is a key element of a novel concept for model-based geometry reconstruction of semiconductor QDs, involving machine learning techniques.
- ItemSymmetries in transmission electron microscopy imaging of crystals with strain(London : [Verlag nicht ermittelbar], 2022) Koprucki, Thomas; Maltsi, Anieza; Mielke, AlexanderTransmission electron microscopy (TEM) images of strained crystals often exhibit symmetries, the source of which is not always clear. To understand these symmetries, we distinguish between symmetries that occur from the imaging process itself and symmetries of the inclusion that might affect the image. For the imaging process, we prove mathematically that the intensities are invariant under specific transformations. A combination of these invariances with specific properties of the strain profile can then explain symmetries observed in TEM images. We demonstrate our approach to the study of symmetries in TEM images using selected examples in the field of semiconductor nanostructures such as quantum wells and quantum dots.
- ItemCorrection to: Numerical simulation of TEM images for In(Ga)As/GaAs quantum dots with various shapes(Dordrecht [u.a.] : Springer Science + Business Media B.V, 2021) Maltsi, Anieza; Niermann, Tore; Streckenbach, Timo; Tabelow, Karsten; Koprucki, ThomasCorrection to: Optical and Quantum Electronics (2020) 52:257 https://doi.org/10.1007/s11082-020-02356-y