title: Low-energy electron scattering in carbon-based materials analyzed by scanning transmission electron microscopy and its application to sample thickness determination.
abstract: High-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) at low energies (≤30 keV) was used to study quantitatively electron scattering in amorphous carbon and carbon-based materials. Experimental HAADF STEM intensities from samples with well-known composition and thickness are compared with results of Monte Carlo simulations and semiempirical equations describing multiple electron scattering. A well-defined relationship is found between the maximum HAADF STEM intensity and sample thickness which is exploited (a) to derive a quantitative description for the mean quadratic scattering angle and (b) to calculate the transmitted HAADF STEM intensity as a function of the relevant materials parameters and electron energy. The formalism can be also applied to determine TEM sample thicknesses by minimizing the contrast of the sample as a function of the electron energy.
authors.affiliation: Laboratorium für Elektronenmikroskopie and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Germany. marina.pfaff@kit.edu
authors.forename: M
authors.initials: M
authors.lastname: Pfaff
authors.forename: E
authors.initials: E
authors.lastname: Müller
authors.forename: M F G
authors.initials: MF
authors.lastname: Klein
authors.forename: A
authors.initials: A
authors.lastname: Colsmann
authors.forename: U
authors.initials: U
authors.lastname: Lemmer
authors.forename: V
authors.initials: V
authors.lastname: Krzyzanek
authors.forename: R
authors.initials: R
authors.lastname: Reichelt
authors.forename: D
authors.initials: D
authors.lastname: Gerthsen