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A silicon p-n junction has been mapped using electron beam induced current in both a scanning transmission electron microscope (STEM) and a conventional scanning electron microscope (SEM). In STEM, the transmission of a higher energy electron beam through the thin specimen leads to better spatial resolution and a more uniform interaction volume than can be achieved in SEM. Better spatial resolution is also achieved in the thin TEM specimens as the diffusion lengths of the minority carriers are much lower than measured in bulk material due to the proximity of specimen surfaces. We further demonstrate that a positive fixed surface charge favors surface recombination of electrons in n-type silicon and induces a surface depletion region in p-type silicon. These results have been compared to off-axis electron holography measurements of the electrostatic potentials and simulations of the internal fields. [ABSTRACT FROM AUTHOR]

Images and spectra obtained from aberration corrected scanning transmission electron microscopes (STEM) are now used routinely to quantify the morphology, structure, composition, chemistry, bonding, and optical/electronic properties of nanostructures, interfaces, and defects in many materials/biological systems. However, obtaining quantitative and reproducible atomic resolution observations from some experiments is actually harder with these ground-breaking instrumental capabilities, as the increase in beam current from using the correctors brings with it the potential for electron beam modification of the specimen during image acquisition. This beam effect is even more acute for in situ STEM observations, where the desired outcome being investigated is a result of a series of complicated transients, all of which can be modified in unknown ways by the electron beam. The aim in developing and applying new methods in STEM is, therefore, to focus on more efficient use of the dose that is supplied to the sample and to extract the most information from each image (or set of images). For STEM (and for that matter, all electron/ion/photon scanning systems), one way to achieve this is by sub-sampling the image and using Inpainting algorithms to reconstruct it. By separating final image quality from overall dose in this way and manipulating the dose distribution to be best for the stability of the sample, images can be acquired both faster and with less beam effects. In this paper, the methodology behind sub-sampling and Inpainting is described, and the potential for Inpainting to be applied to novel real time dynamic experiments will be discussed. [ABSTRACT FROM AUTHOR]

Good specimen quality is a key factor in achieving successful scanning transmission electron microscope analysis. Thin and damage-free specimens are prerequisites for obtaining atomic-resolution imaging. Topological insulator single crystals and thin films in the chalcogenide family such as Sb2Te3 are sensitive to electron and ion beams. It is, therefore, challenging to prepare a lamella suitable for high-resolution imaging from these topological insulator materials using standard focused ion-beam instruments. We have developed a modified method to fabricate thin focused ion-beam (FIB) lamellae with minimal ion-beam damage and artifacts. The technique described in the current study enables the reliable preparation of high-quality transmission electron microscope (TEM) specimens necessary for studying ultra-thin surface regions. We have successfully demonstrated that the careful selection of FIB milling parameters at each stage minimizes the damage layer without the need for post-treatment. [ABSTRACT FROM AUTHOR]

Subsampled image acquisition followed by image inpainting in a scanning transmission electron microscope is a novel approach to control dose and increase the image frame rate during experiments, thereby allowing independent control of the spatial and temporal dose envelope during image acquisition. Here, subsampled imaging is shown to permit precise in situ observations of the fundamental kinetic processes behind nucleation and growth of silver (Ag) nanoparticles from an aqueous solution. At high sampling-levels, nanoparticles can be observed with morphologies that are consistent with strong interface interactions, i.e., rafts and pillars, whereas at low sampling-levels, the particles exhibit regular spherical morphologies. The relative numbers of rafts/pillars and regular nanoparticles, their sizes, and their incubation times can be attributed to local changes in the molar concentration of the Ag ions in the aqueous solution; higher sampling-levels significantly increase the reactants in the vicinity of the window, leading to rapid supersaturation and the precipitation on the window surface. These precisely controlled kinetics highlight subsampled imaging as a method by which the driving force for nucleation and growth (i.e., the electron beam) can be disentangled from the spatial/temporal resolution of the observation in all in situ experiments, providing a pathway to identify and quantify the importance of individual kinetic factors behind nucleation and growth in a wide variety of complex materials systems and architectures. [ABSTRACT FROM AUTHOR]

Modification of silicon nitride nanopores under electron beam (e-beam) irradiation was investigated using a scanning electron microscope (SEM). Under e-beam irradiation, all pores with diameters ranging from 40 to 200 nm undergo shrinkage, and the shrinkage rate increases with the rate of energy deposition. By using the selected-area scanning tool in the SEM, the silicon nitride nanopores can be selectively reshaped based on localized e-beam irradiation, with a characteristic dimension smaller than 10 nm. A selected-area shaping technique was proposed to controllably shrink and shape the nanopores to a special structure. [ABSTRACT FROM AUTHOR]