Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 52: Topical session: In-situ Microscopy with Electrons, X-Rays and Scanning Probes in Materials Science VI - Structural transitions

MM 52.5: Vortrag

Donnerstag, 10. März 2016, 13:00–13:15, H38

Transmission electron microscopy image and energy-dispersive X-ray map simulations of Ga-covered Pb nanoparticles embedded in an Al matrix. — •Martin Peterlechner and Gerhard Wilde — Institut für Materialphysik, WWU Münster, Münster, Deutschland

Nanoparticles are in focus of research since decades due to their size effects. Embedded nanoparticles in a matrix show additional effects caused by their interface structure. In the present study, the simulation of transmission electron microscopy (TEM) images is focused. High-resolution TEM (HRTEM) contrast, Scanning-TEM (STEM) contrast and energy-dispersive X-ray (EDX) maps are elucidated. A simple atomistic model of an Al matrix with Ga-covered embedded Pb nanoparticles was chosen to study moiré contributions and thickness effects for contrast formation. HRTEM images of the as-generated structures were simulated using the multislice algorithm by Kirkland, and STEM/EDX micrographs were simulated using muSTEM by D'Alfonso, Findlay and Allen. The spacing of the moiré pattern can be used to determine the difference of the involved lattice planes with a high accuracy, however, measurements of absolute atomic positions are not always possible since atoms can become 'invisible' at local regions of the moiré pattern. Moreover, apparent interface roughening can occur by moiré effects. The EDX signal of the Ga atoms is blurred with increasing thickness. Therefore, image simulation is inevitable to interpret atomic positions and chemistry at interfaces, in particular when a nanoparticle is embedded and not of constant thickness.