Variable-resolution fluctuation electron microscopy (VR-FEM) data from measurements on amorphous silicon and PdNiP have been obtained at varying experimental conditions. Measurements have been conducted at identical total electron dose and with an identical electron dose normalized to the respective probe size. STEM probes of different sizes have been created by variation of the semi-convergence angle or by defocus. The results show that defocus yields a reduced normalized variance compared to data from probes created by convergence angle variation. Moreover, the trend of the normalized variance upon probe size variation differs between the two methods. Beam coherence, which affects FEM data, has been analyzed theoretically using geometrical optics on a multi-lens setup and linked to the illumination conditions. Fits to several experimental beam profiles support our geometrical optics theory regarding probe coherence. The normalized variance can be further optimized if one determines the optimal exposure time for the nanobeam diffraction patterns.

A hybrid nanobeam diffraction/imaging method, which combines well-developed diffraction imaging with nanobeam diffraction (NBD) pattern analysis, is described for structural mapping of disordered materials. Spatially resolved crystallographic information is obtained by NBD imaging by collecting NBD patterns at predefined intervals within a field of interest. The resulting dataset of NBD patterns is preprocessed to produce a spectral-imaging-like dataset and is further analyzed via multivariate statistical analysis methods in order to extract the relevant structural components and their distribution within the area of the sample under study without prior knowledge. Additional radial distribution function analysis of either the principal components or averaged data provides real-space maps of short-range order within the field of interest. This technique is demonstrated for two systems, one with multiple amorphous phases and one with multiple phases (amorphous and nanocrystalline) with similar chemistry.

We evaluate the probe forming capability of a JEOL 2200FS transmission electron microscope equipped with a spherical aberration (Cs) probe corrector. The achievement of a real space sub-Angstrom (0.1 nm) probe for scanning transmission electron microscopy (STEM) imaging is demonstrated by acquisition and modeling of high-angle annular dark-field STEM images. We show that by optimizing the illumination system, large probe currents and large collection angles for electron energy loss spectroscopy (EELS) can be combined to yield EELS fine structure data spatially resolved to the atomic scale. We demonstrate the probe forming flexibility provided by the additional lenses in the probe corrector in several ways, including the formation of nanometer-sized parallel beams for nanoarea electron diffraction, and the formation of focused probes for convergent beam electron diffraction with a range of convergence angles. The different probes that can be formed using the probe corrected STEM opens up new applications for electron microscopy and diffraction.