Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 17: Topical Session: TEM-Symposium - HR Imaging & Analytic I

MM 17.1: Topical Talk

Dienstag, 12. März 2013, 10:15–10:45, H4

Quantification of sample properties by low-energy scanning transmission electron microscopy — Erich Müller, Holger Blank, Marina Pfaff, Tobias Volkenandt, and •Dagmar Gerthsen — Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie (KIT), Karlsruhe, Germany

Scanning transmission electron microscopy (STEM) at low energies (< 30 keV) is a promising technique for microstructure analysis and quantification of sample properties. Low-energy STEM images can be taken in a standard scanning electron microscope which is equipped with a STEM detector. Using thin samples a high lateral resolution in the order of 1 nm can be achieved which is sufficient for many materials science and biological applications. Modelling of the STEM image intensity at low electron energies can be performed by Monte-Carlo simulations, which is considerably less complex than STEM image simulations at high electron energies. Quantification of the sample information (local sample thickness and composition) can be performed by comparison of simulated and experimental STEM intensities.

High-angle annular dark-field STEM is particularly interesting because the chemical sensitivity of this particular imaging mode increases with decreasing electron energy. The high chemical sensitivity can be exploited for the study of samples which provide low contrast as, e.g., polymers and biological objects. We will show applications of low-energy STEM in materials science and biology with a particular focus on quantification of the sample thickness and sample composition in compound semiconductors.