The performance evaluation of direct detection electron energy-loss spectroscopy at 200 kV and 80 kV accelerating voltages.

Direct electron detectors (DeDs) have been widely used for imaging studies because of their higher beam sensitivity, lower noise, improved pixel resolution, etc. However, there have been limited studies related to the performance in spectroscopic applications for the direct electron detection. Hereby, taking the advantage of the DeD installed on a high-performance electron energy-loss spectrometer, we systematically studied the performance of a DeD (Gatan's K2 IS) fitted on an aberration-corrected transmission electron microscope (TEM) equipped with an electron monochromator.

Direct Detection Electron Energy-Loss Spectroscopy: A Method to Push the Limits of Resolution and Sensitivity.

In many cases, electron counting with direct detection sensors offers improved resolution, lower noise, and higher pixel density compared to conventional, indirect detection sensors for electron microscopy applications. Direct detection technology has previously been utilized, with great success, for imaging and diffraction, but potential advantages for spectroscopy remain unexplored. Here we compare the performance of a direct detection sensor operated in counting mode and an indirect detection sensor (scintillator/fiber-optic/CCD) for electron energy-loss spectroscopy.

Interface-induced nonswitchable domains in ferroelectric thin films.

Engineering domains in ferroelectric thin films is crucial for realizing technological applications including non-volatile data storage and solar energy harvesting. Size and shape of domains strongly depend on the electrical and mechanical boundary conditions. Here we report the origin of nonswitchable polarization under external bias that leads to energetically unfavourable head-to-head domain walls in as-grown epitaxial PbZr(0.

Probing the chemical structure in diamond-based materials using combined low-loss and core-loss electron energy-loss spectroscopy.

We report the analysis of the changes in local carbon structure and chemistry caused by the self-implantation of carbon into diamond via electron energy-loss spectroscopy (EELS) plasmon energy shifts and core-edge fine structure fingerprinting. These two very different EELS energy and intensity ranges of the spectrum can be acquired under identical experimental conditions and nearly simultaneously using specially designed deflectors and energy offset devices known as "DualEELS." In this way, it is possible to take full advantage of the unique and complementary information that is present in the low- and core-loss regions of the EELS spectrum.

Review of recent advances in spectrum imaging and its extension to reciprocal space.

Using examples from various domains of science, this review covers some recent developments in spectrum imaging (SI) using scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS). Advanced multi-dimensional acquisition methods allow the acquisition of STEM-EELS data with other complementary data such as energy dispersive X-ray spectroscopy (EDS), cathodoluminescence and even combining them with reciprocal space analysis through a new method called diffraction imaging. This method allows real and reciprocal space information to be mixed to get a more complete description of the electron-sample interaction.

Four-dimensional STEM-EELS: enabling nano-scale chemical tomography.

Advances in electron-based instrumentation have enabled the acquisition of multidimensional data sets for exploring the unique structure-property relationship of nanomaterials. In this manuscript, we report a technique for directly probing and analyzing the three-dimensional (3D) electronic structure of a material at the nano-scale. This technique, referred to here as 4D STEM-EELS, utilizes a rotation holder and pillar-shaped samples to allow STEM mode high-angle annular dark-field (HAADF) and EELS spectrum images to be recorded over a complete 180 degrees rotation to minimize artifacts.

Fast, completely reversible li insertion in vanadium pentoxide nanoribbons.

Layered-structure nanoribbons with efficient electron transport and short lithium ion insertion lengths are promising candidates for Li battery applications. Here we studied at the single nanostructure level the chemical, structural, and electrical transformations of V2O5 nanoribbons. We found that transformation of V2O5 into the omega-Li3V2O5 phase depends not only on the width but also the thickness of the nanoribbons.

Metal core bonding motifs of monodisperse icosahedral Au13 and larger Au monolayer-protected clusters as revealed by X-ray absorption spectroscopy and transmission electron microscopy.

The atomic metal core structures of the subnanometer clusters Au13[PPh3]4[S(CH2)11CH3]2Cl2 (1) and Au13[PPh3]4[S(CH2)11CH3]4 (2) were characterized using advanced methods of electron microscopy and X-ray absorption spectroscopy. The number of gold atoms in the cores of these two clusters was determined quantitatively using high-angle annular dark field scanning transmission electron microscopy. Multiple-scattering-path analyses of extended X-ray absorption fine structure (EXAFS) spectra suggest that the Au metal cores of each of these complexes adopt an icosahedral structure with a relaxation of the icosahedral strain.

Sub-nanometer Au monolayer-protected clusters exhibiting molecule-like electronic behavior: quantitative high-angle annular dark-field scanning transmission electron microscopy and electrochemical characterization of clusters with precise atomic stoichiometry.

The synthesis and characterization of the clusters Au13[PPh3]4[S(CH2)11CH3]2Cl2 (1) and Au13[PPh3]4[S(CH2)11CH3]4 (2) are described. These mixed-ligand, sub-nanometer clusters, prepared via exchange of dodecanethiol onto phosphine-halide gold clusters, show enhanced stability relative to the parent. The characterization of these clusters features the precise determination of the number of gold atoms in the cluster cores using high-angle annular dark-field scanning transmission electron microscopy, allowing the assignment of 13 gold atoms (+/-3 atoms) to the composition of both cluster molecules.

Physical evidence that yeast frataxin is an iron storage protein.

Frataxin is a conserved mitochondrial protein required for iron homeostasis. We showed previously that in the presence of ferrous iron recombinant yeast frataxin (mYfh1p) assembles into a regular multimer of approximately 1.1 MDa storing approximately 3000 iron atoms.